diff --git a/core/serialization/blocks.js b/core/serialization/blocks.js
index 1ad9b57b439..4ab79a3a45b 100644
--- a/core/serialization/blocks.js
+++ b/core/serialization/blocks.js
@@ -15,11 +15,25 @@ goog.module.declareLegacyNamespace();
 
 // eslint-disable-next-line no-unused-vars
 const Block = goog.requireType('Blockly.Block');
+// eslint-disable-next-line no-unused-vars
+const Connection = goog.requireType('Blockly.Connection');
+const Xml = goog.require('Blockly.Xml');
+const inputTypes = goog.require('Blockly.inputTypes');
 
 
 // TODO: Remove this once lint is fixed.
 /* eslint-disable no-use-before-define */
 
+/**
+ * Represents the state of a connection.
+ * @typedef {{
+ *   shadow: (!State|undefined),
+ *   block: (!State|undefined)
+ * }}
+ */
+var ConnectionState;
+exports.ConnectionState = ConnectionState;
+
 /**
  * Represents the state of a given block.
  * @typedef {{
@@ -35,7 +49,9 @@ const Block = goog.requireType('Blockly.Block');
  *     inline: (boolean|undefined),
  *     data: (string|undefined),
  *     extra-state: *,
- *     fields: (Object<string, *>|undefined),
+ *     fields: (!Object<string, *>|undefined),
+ *     inputs: (!Object<string, !ConnectionState>|undefined),
+ *     next: (!ConnectionState|undefined)
  * }}
  */
 var State;
@@ -44,14 +60,27 @@ exports.State = State;
 /**
  * Returns the state of the given block as a plain JavaScript object.
  * @param {!Block} block The block to serialize.
- * @param {{addCoordinates: (boolean|undefined)}=} param1
- *     addCoordinates: If true the coordinates of the block are added to the
+ * @param {{addCoordinates: (boolean|undefined), addInputBlocks:
+ *     (boolean|undefined), addNextBlocks: (boolean|undefined)}=} param1
+ *     addCoordinates: If true, the coordinates of the block are added to the
  *       serialized state. False by default.
+ *     addinputBlocks: If true, children of the block which are connected to
+ *       inputs will be serialized. True by default.
+ *     addNextBlocks: If true, children of the block which are connected to the
+ *       block's next connection (if it exists) will be serialized.
+ *       True by default.
  * @return {?State} The serialized state of the
  *     block, or null if the block could not be serialied (eg it was an
  *     insertion marker).
  */
-const save = function(block, {addCoordinates = false} = {}) {
+const save = function(
+    block,
+    {
+      addCoordinates = false,
+      addInputBlocks = true,
+      addNextBlocks = true
+    } = {}
+) {
   if (block.isInsertionMarker()) {
     return null;
   }
@@ -62,11 +91,17 @@ const save = function(block, {addCoordinates = false} = {}) {
   };
 
   if (addCoordinates) {
-    addCoords(block, state);
+    saveCoords(block, state);
+  }
+  saveAttributes(block, state);
+  saveExtraState(block, state);
+  saveFields(block, state);
+  if (addInputBlocks) {
+    saveInputBlocks(block, state);
+  }
+  if (addNextBlocks) {
+    saveNextBlocks(block, state);
   }
-  addAttributes(block, state);
-  addExtraState(block, state);
-  addFields(block, state);
 
   return state;
 };
@@ -78,7 +113,7 @@ exports.save = save;
  * @param {!Block} block The block to base the attributes on.
  * @param {!State} state The state object to append to.
  */
-const addAttributes = function(block, state) {
+const saveAttributes = function(block, state) {
   if (block.isCollapsed()) {
     state['collapsed'] = true;
   }
@@ -111,7 +146,7 @@ const addAttributes = function(block, state) {
  * @param {!Block} block The block to base the coordinates on
  * @param {!State} state The state object to append to
  */
-const addCoords = function(block, state) {
+const saveCoords = function(block, state) {
   const workspace = block.workspace;
   const xy = block.getRelativeToSurfaceXY();
   state['x'] = Math.round(workspace.RTL ? workspace.getWidth() - xy.x : xy.x);
@@ -123,7 +158,7 @@ const addCoords = function(block, state) {
  * @param {!Block} block The block to serialize the extra state of.
  * @param {!State} state The state object to append to.
  */
-const addExtraState = function(block, state) {
+const saveExtraState = function(block, state) {
   if (block.saveExtraState) {
     const extraState = block.saveExtraState();
     if (extraState !== null) {
@@ -137,7 +172,7 @@ const addExtraState = function(block, state) {
  * @param {!Block} block The block to serialize the field state of.
  * @param {!State} state The state object to append to.
  */
-const addFields = function(block, state) {
+const saveFields = function(block, state) {
   let hasFieldState = false;
   let fields = Object.create(null);
   for (let i = 0; i < block.inputList.length; i++) {
@@ -154,3 +189,69 @@ const addFields = function(block, state) {
     state['fields'] = fields;
   }
 };
+
+/**
+ * Adds the state of all of the child blocks of the given block (which are
+ * connected to inputs) to the given state object.
+ * @param {!Block} block The block to serialize the input blocks of.
+ * @param {!State} state The state object to append to.
+ */
+const saveInputBlocks = function(block, state) {
+  const inputs = Object.create(null);
+  for (let i = 0; i < block.inputList.length; i++) {
+    const input = block.inputList[i];
+    if (input.type === inputTypes.DUMMY) {
+      continue;
+    }
+    const connectionState =
+        saveConnection(/** @type {!Connection} */ (input.connection));
+    if (connectionState) {
+      inputs[input.name] = connectionState;
+    }
+  }
+
+  if (Object.keys(inputs).length) {
+    state['inputs'] = inputs;
+  }
+};
+
+/**
+ * Adds the state of all of the next blocks of the given block to the given
+ * state object.
+ * @param {!Block} block The block to serialize the next blocks of.
+ * @param {!State} state The state object to append to.
+ */
+const saveNextBlocks = function(block, state) {
+  if (!block.nextConnection) {
+    return;
+  }
+  const connectionState = saveConnection(block.nextConnection);
+  if (connectionState) {
+    state['next'] = connectionState;
+  }
+};
+
+/**
+ * Returns the state of the given connection (ie the state of any connected
+ * shadow or real blocks).
+ * @param {!Connection} connection The connection to serialize the connected
+ *     blocks of.
+ * @return {?ConnectionState} An object containing the state of any connected
+ *     shadow block, or any connected real block.
+ */
+const saveConnection = function(connection) {
+  const shadow = connection.getShadowDom();
+  const child = connection.targetBlock();
+  if (!shadow && !child) {
+    return null;
+  }
+  var state = Object.create(null);
+  if (shadow) {
+    state['shadow'] = Xml.domToText(shadow)
+        .replace('xmlns="https://developers.google.com/blockly/xml"', '');
+  }
+  if (child) {
+    state['block'] = save(child);
+  }
+  return state;
+};
diff --git a/tests/deps.js b/tests/deps.js
index bf85399f873..43cdc5eb452 100644
--- a/tests/deps.js
+++ b/tests/deps.js
@@ -196,7 +196,7 @@ goog.addDependency('../../core/renderers/zelos/renderer.js', ['Blockly.zelos.Ren
 goog.addDependency('../../core/requires.js', ['Blockly.requires'], ['Blockly', 'Blockly.Comment', 'Blockly.ContextMenuItems', 'Blockly.FieldAngle', 'Blockly.FieldCheckbox', 'Blockly.FieldColour', 'Blockly.FieldDropdown', 'Blockly.FieldImage', 'Blockly.FieldLabelSerializable', 'Blockly.FieldMultilineInput', 'Blockly.FieldNumber', 'Blockly.FieldTextInput', 'Blockly.FieldVariable', 'Blockly.FlyoutButton', 'Blockly.Generator', 'Blockly.HorizontalFlyout', 'Blockly.Mutator', 'Blockly.ShortcutItems', 'Blockly.Themes.Classic', 'Blockly.Toolbox', 'Blockly.Trashcan', 'Blockly.VariablesDynamic', 'Blockly.VerticalFlyout', 'Blockly.Warning', 'Blockly.ZoomControls', 'Blockly.geras.Renderer', 'Blockly.serialization.blocks', 'Blockly.thrasos.Renderer', 'Blockly.zelos.Renderer']);
 goog.addDependency('../../core/scrollbar.js', ['Blockly.Scrollbar'], ['Blockly.Touch', 'Blockly.browserEvents', 'Blockly.utils', 'Blockly.utils.Coordinate', 'Blockly.utils.Svg', 'Blockly.utils.dom'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/scrollbar_pair.js', ['Blockly.ScrollbarPair'], ['Blockly.Events', 'Blockly.Scrollbar', 'Blockly.utils.Svg', 'Blockly.utils.dom'], {'lang': 'es6', 'module': 'goog'});
-goog.addDependency('../../core/serialization/blocks.js', ['Blockly.serialization.blocks'], [], {'lang': 'es6', 'module': 'goog'});
+goog.addDependency('../../core/serialization/blocks.js', ['Blockly.serialization.blocks'], ['Blockly.Xml', 'Blockly.inputTypes'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/serialization/serialization.js', ['Blockly.serialization'], [], {'module': 'goog'});
 goog.addDependency('../../core/shortcut_items.js', ['Blockly.ShortcutItems'], ['Blockly.Gesture', 'Blockly.ShortcutRegistry', 'Blockly.clipboard', 'Blockly.common', 'Blockly.utils.KeyCodes'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/shortcut_registry.js', ['Blockly.ShortcutRegistry'], ['Blockly.utils.KeyCodes', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
diff --git a/tests/mocha/jso_serialization_test.js b/tests/mocha/jso_serialization_test.js
index 3b46355472b..c6fe395252b 100644
--- a/tests/mocha/jso_serialization_test.js
+++ b/tests/mocha/jso_serialization_test.js
@@ -343,5 +343,295 @@ suite('JSO', function() {
         assertProperty(jso, 'fields', {'FIELD': ['state1', 42, true]});
       });
     });
+
+    suite('Connected blocks', function() {
+      setup(function() {
+        this.assertInput = function(jso, name, value) {
+          chai.assert.deepInclude(jso['inputs'][name], value);
+        };
+
+        this.createBlockWithChild = function(blockType, inputName) {
+          const block = this.workspace.newBlock(blockType);
+          const childBlock = this.workspace.newBlock(blockType);
+          block.getInput(inputName).connection.connect(
+              childBlock.outputConnection || childBlock.previousConnection);
+          return block;
+        };
+
+        this.createBlockWithShadow = function(blockType, inputName) {
+          const block = this.workspace.newBlock(blockType);
+          block.getInput(inputName).connection.setShadowDom(
+              Blockly.Xml.textToDom(
+                  '<block type="' + blockType + '" id="test"></block>'));
+          return block;
+        };
+
+        this.createBlockWithShadowAndChild = function(blockType, inputName) {
+          const block = this.workspace.newBlock(blockType);
+          const childBlock = this.workspace.newBlock(blockType);
+          block.getInput(inputName).connection.connect(
+              childBlock.outputConnection || childBlock.previousConnection);
+          block.getInput(inputName).connection.setShadowDom(
+              Blockly.Xml.textToDom(
+                  '<block type="' + blockType + '" id="test"></block>'));
+          return block;
+        };
+  
+        this.assertChild = function(blockType, inputName) {
+          const block = this.createBlockWithChild(blockType, inputName);
+          const jso = Blockly.serialization.blocks.save(block);
+          this.assertInput(
+              jso, inputName, {'block': { 'type': blockType, 'id': 'id2'}});
+        };
+  
+        this.assertShadow = function(blockType, inputName) {
+          const block = this.createBlockWithShadow(blockType, inputName);
+          const jso = Blockly.serialization.blocks.save(block);
+          this.assertInput(
+              jso, inputName, {'shadow': { 'type': blockType, 'id': 'test'}});
+        };
+  
+        this.assertOverwrittenShadow = function(blockType, inputName) {
+          const block =
+              this.createBlockWithShadowAndChild(blockType, inputName);
+          const jso = Blockly.serialization.blocks.save(block);
+          this.assertInput(
+              jso,
+              inputName,
+              {
+                'block': {
+                  'type': blockType,
+                  'id': 'id2'
+                },
+                'shadow': {
+                  'type': blockType,
+                  'id': 'test'
+                }
+              });
+        };
+
+        this.assertNoChild = function(blockType, inputName) {
+          const block = this.createBlockWithChild(blockType, inputName);
+          const jso =
+              Blockly.serialization.blocks.save(block, {addInputBlocks: false});
+          chai.assert.isUndefined(jso['inputs']);
+        };
+  
+        this.assertNoShadow = function(blockType, inputName) {
+          const block = this.createBlockWithShadow(blockType, inputName);
+          const jso =
+              Blockly.serialization.blocks.save(block, {addInputBlocks: false});
+          chai.assert.isUndefined(jso['inputs']);
+        };
+  
+        this.assertNoOverwrittenShadow = function(blockType, inputName) {
+          const block =
+              this.createBlockWithShadowAndChild(blockType, inputName);
+          const jso =
+              Blockly.serialization.blocks.save(block, {addInputBlocks: false});
+          chai.assert.isUndefined(jso['inputs']);
+        };
+      });
+
+      suite('Value', function() {
+        suite('With serialization', function() {
+          test('Child', function() {
+            this.assertChild('row_block', 'INPUT');
+          });
+  
+          test.skip('Shadow', function() {
+            this.assertShadow('row_block', 'INPUT');
+          });
+  
+          test.skip('Overwritten shadow', function() {
+            this.assertOverwrittenShadow('row_block', 'INPUT');
+          });
+        });
+
+        suite('Without serialization', function() {
+          test('Child', function() {
+            this.assertNoChild('row_block', 'INPUT');
+          });
+  
+          test('Shadow', function() {
+            this.assertNoShadow('row_block', 'INPUT');
+          });
+  
+          test('Overwritten shadow', function() {
+            this.assertNoOverwrittenShadow('row_block', 'INPUT');
+          });
+        });
+      });
+
+      suite('Statement', function() {
+        suite('With serialization', function() {
+          test('Child', function() {
+            this.assertChild('statement_block', 'NAME');
+          });
+  
+          test.skip('Shadow', function() {
+            this.assertShadow('statement_block', 'NAME');
+          });
+  
+          test.skip('Overwritten shadow', function() {
+            this.assertOverwrittenShadow('statement_block', 'NAME');
+          });
+
+          test('Child with next blocks', function() {
+            const block = this.workspace.newBlock('statement_block');
+            const childBlock = this.workspace.newBlock('stack_block');
+            const grandChildBlock = this.workspace.newBlock('stack_block');
+            block.getInput('NAME').connection
+                .connect(childBlock.previousConnection);
+            childBlock.nextConnection
+                .connect(grandChildBlock.previousConnection);
+            const jso = Blockly.serialization.blocks.save(block);
+            this.assertInput(
+                jso,
+                'NAME',
+                {
+                  'block': {
+                    'type': 'stack_block',
+                    'id': 'id2',
+                    'next': {
+                      'block': {
+                        'type': 'stack_block',
+                        'id': 'id4'
+                      }
+                    }
+                  }
+                }
+            );
+          });
+        });
+
+        suite('Without serialization', function() {
+          test('Child', function() {
+            this.assertNoChild('statement_block', 'NAME');
+          });
+  
+          test('Shadow', function() {
+            this.assertNoShadow('statement_block', 'NAME');
+          });
+  
+          test('Overwritten shadow', function() {
+            this.assertNoOverwrittenShadow('statement_block', 'NAME');
+          });
+        });
+      });
+
+      suite('Next', function() {
+        setup(function() {
+          this.createNextWithChild = function() {
+            const block = this.workspace.newBlock('stack_block');
+            const childBlock = this.workspace.newBlock('stack_block');
+            block.nextConnection.connect(childBlock.previousConnection);
+            return block;
+          };
+
+          this.createNextWithShadow = function() {
+            const block = this.workspace.newBlock('stack_block');
+            block.nextConnection.setShadowDom(
+                Blockly.Xml.textToDom(
+                    '<block type="stack_block" id="test"></block>'));
+            return block;
+          };
+
+          this.createNextWithShadowAndChild = function() {
+            const block = this.workspace.newBlock('stack_block');
+            const childBlock = this.workspace.newBlock('stack_block');
+            block.nextConnection.connect(childBlock.previousConnection);
+            block.nextConnection.setShadowDom(
+                Blockly.Xml.textToDom(
+                    '<block type="stack_block" id="test"></block>'));
+            return block;
+          };
+        });
+
+        suite('With serialization', function() {
+          test('Child', function() {
+            const block = this.createNextWithChild();
+            const jso =
+                Blockly.serialization.blocks.save(block);
+            chai.assert.deepInclude(
+                jso['next'], {'block': { 'type': 'stack_block', 'id': 'id2'}});
+          });
+  
+          test.skip('Shadow', function() {
+            const block = this.createNextWithShadow();
+            const jso = Blockly.serialization.blocks.save(block);
+            chai.assert.deepInclude(
+                jso['next'], {'shadow': { 'type': 'stack_block', 'id': 'test'}});
+          });
+  
+          test.skip('Overwritten shadow', function() {
+            const block = this.createNextWithShadowAndChild();
+            const jso = Blockly.serialization.blocks.save(block);
+            chai.assert.deepInclude(
+                jso['next'],
+                {
+                  'block': {
+                    'type': 'stack_block',
+                    'id': 'id2'
+                  },
+                  'shadow': {
+                    'type': 'stack_block',
+                    'id': 'test'
+                  }
+                });
+          });
+
+          test('Next block with inputs', function() {
+            const block = this.workspace.newBlock('stack_block');
+            const childBlock = this.workspace.newBlock('statement_block');
+            const grandChildBlock = this.workspace.newBlock('stack_block');
+            block.nextConnection.connect(childBlock.previousConnection);
+            childBlock.getInput('NAME').connection
+                .connect(grandChildBlock.previousConnection);
+            const jso = Blockly.serialization.blocks.save(block);
+            chai.assert.deepInclude(
+                jso['next'],
+                {
+                  'block': {
+                    'type': 'statement_block',
+                    'id': 'id2',
+                    'inputs': {
+                      'NAME': {
+                        'block': {
+                          'type': 'stack_block',
+                          'id': 'id4'
+                        }
+                      }
+                    }
+                  }
+                }
+            );
+          });
+        });
+
+        suite('Without serialization', function() {
+          test('Child', function() {
+            const block = this.createNextWithChild();
+            const jso = Blockly.serialization.blocks.save(
+                block, {addNextBlocks: false});
+            chai.assert.isUndefined(jso['next']);
+          });
+  
+          test('Shadow', function() {
+            const block = this.createNextWithShadow();
+            const jso = Blockly.serialization.blocks.save(
+                block, {addNextBlocks: false});
+            chai.assert.isUndefined(jso['next']);
+          });
+
+          test('Overwritten shadow', function() {
+            const block = this.createNextWithShadowAndChild();
+            const jso = Blockly.serialization.blocks.save(
+                block, {addNextBlocks: false});
+            chai.assert.isUndefined(jso['next']);
+          });
+        });
+      });
+    });
   });
 });