diff --git a/plugins/node/opentelemetry-instrumentation-fastify/README.md b/plugins/node/opentelemetry-instrumentation-fastify/README.md
index 9835aa225b..89c4a6e1d0 100644
--- a/plugins/node/opentelemetry-instrumentation-fastify/README.md
+++ b/plugins/node/opentelemetry-instrumentation-fastify/README.md
@@ -17,7 +17,7 @@ npm install --save @opentelemetry/instrumentation-http @opentelemetry/instrument
 
 ### Supported Versions
 
-- `^3.0.0`
+- fastify: `^3.0.0 || ^4.0.0`
 
 ## Usage
 
diff --git a/plugins/node/opentelemetry-instrumentation-fastify/package.json b/plugins/node/opentelemetry-instrumentation-fastify/package.json
index 65d3a7f959..672c06fbcf 100644
--- a/plugins/node/opentelemetry-instrumentation-fastify/package.json
+++ b/plugins/node/opentelemetry-instrumentation-fastify/package.json
@@ -45,15 +45,15 @@
     "@opentelemetry/api": "^1.0.0"
   },
   "devDependencies": {
+    "@fastify/express": "^2.0.2",
     "@opentelemetry/api": "^1.0.0",
     "@opentelemetry/context-async-hooks": "^1.3.1",
     "@opentelemetry/instrumentation-http": "0.30.0",
-    "@opentelemetry/sdk-trace-node": "^1.3.1",
     "@opentelemetry/sdk-trace-base": "^1.3.1",
+    "@opentelemetry/sdk-trace-node": "^1.3.1",
     "@types/express": "4.17.13",
     "@types/mocha": "7.0.2",
     "@types/node": "16.11.21",
-    "fastify-express": "0.3.3",
     "gts": "3.1.0",
     "mocha": "7.2.0",
     "nyc": "15.1.0",
@@ -65,7 +65,7 @@
     "@opentelemetry/core": "^1.0.0",
     "@opentelemetry/instrumentation": "^0.32.0",
     "@opentelemetry/semantic-conventions": "^1.0.0",
-    "fastify": "^3.19.2"
+    "fastify": "^4.5.3"
   },
   "homepage": "https://github.com/open-telemetry/opentelemetry-js-contrib/tree/main/plugins/node/opentelemetry-instrumentation-fastify#readme"
 }
diff --git a/plugins/node/opentelemetry-instrumentation-fastify/src/instrumentation.ts b/plugins/node/opentelemetry-instrumentation-fastify/src/instrumentation.ts
index cfe666c559..b267f03336 100644
--- a/plugins/node/opentelemetry-instrumentation-fastify/src/instrumentation.ts
+++ b/plugins/node/opentelemetry-instrumentation-fastify/src/instrumentation.ts
@@ -62,7 +62,7 @@ export class FastifyInstrumentation extends InstrumentationBase {
     return [
       new InstrumentationNodeModuleDefinition<any>(
         'fastify',
-        ['^3.0.0'],
+        ['^3.0.0', '^4.0.0'],
         (moduleExports, moduleVersion) => {
           this._diag.debug(`Applying patch for fastify@${moduleVersion}`);
           return this._patchConstructor(moduleExports);
@@ -100,6 +100,8 @@ export class FastifyInstrumentation extends InstrumentationBase {
     syncFunctionWithDone: boolean
   ): () => Promise<unknown> {
     const instrumentation = this;
+    this._diag.debug('Patching fastify route.handler function');
+
     return function (this: any, ...args: unknown[]): Promise<unknown> {
       if (!instrumentation.isEnabled()) {
         return original.apply(this, args);
@@ -156,6 +158,8 @@ export class FastifyInstrumentation extends InstrumentationBase {
     original: FastifyInstance['addHook']
   ) => () => FastifyInstance {
     const instrumentation = this;
+    this._diag.debug('Patching fastify server.addHook function');
+
     return function (
       original: FastifyInstance['addHook']
     ): () => FastifyInstance {
@@ -188,6 +192,7 @@ export class FastifyInstrumentation extends InstrumentationBase {
     original: () => FastifyInstance
   ): () => FastifyInstance {
     const instrumentation = this;
+    this._diag.debug('Patching fastify constructor function');
 
     function fastify(this: FastifyInstance, ...args: any) {
       const app: FastifyInstance = original.apply(this, args);
@@ -206,6 +211,8 @@ export class FastifyInstrumentation extends InstrumentationBase {
 
   public _patchSend() {
     const instrumentation = this;
+    this._diag.debug('Patching fastify reply.send function');
+
     return function patchSend(
       original: () => FastifyReply
     ): () => FastifyReply {
@@ -233,6 +240,8 @@ export class FastifyInstrumentation extends InstrumentationBase {
 
   public _hookPreHandler() {
     const instrumentation = this;
+    this._diag.debug('Patching fastify preHandler function');
+
     return function preHandler(
       this: any,
       request: FastifyRequest,
diff --git a/plugins/node/opentelemetry-instrumentation-fastify/test/instrumentation.test.ts b/plugins/node/opentelemetry-instrumentation-fastify/test/instrumentation.test.ts
index 8588c24c60..aa17f3b246 100644
--- a/plugins/node/opentelemetry-instrumentation-fastify/test/instrumentation.test.ts
+++ b/plugins/node/opentelemetry-instrumentation-fastify/test/instrumentation.test.ts
@@ -67,7 +67,7 @@ provider.addSpanProcessor(spanProcessor);
 instrumentation.enable();
 httpInstrumentation.enable();
 
-import 'fastify-express';
+import '@fastify/express';
 import { FastifyInstance } from 'fastify/types/instance';
 
 const Fastify = require('fastify');
@@ -94,7 +94,7 @@ describe('fastify', () => {
   let app: FastifyInstance;
 
   async function startServer(): Promise<void> {
-    const address = await app.listen(0);
+    const address = await app.listen({ port: 0 });
     const url = new URL(address);
     PORT = parseInt(url.port, 10);
   }
@@ -102,7 +102,7 @@ describe('fastify', () => {
   beforeEach(async () => {
     instrumentation.enable();
     app = Fastify();
-    app.register(require('fastify-express'));
+    app.register(require('@fastify/express'));
   });
 
   afterEach(async () => {
@@ -145,7 +145,7 @@ describe('fastify', () => {
       const span = spans[3];
       assert.deepStrictEqual(span.attributes, {
         'fastify.type': 'request_handler',
-        'plugin.name': 'fastify-express',
+        'plugin.name': 'fastify -> @fastify/express',
         [SemanticAttributes.HTTP_ROUTE]: '/test',
       });
       assert.strictEqual(span.name, `request handler - ${ANONYMOUS_NAME}`);
@@ -168,7 +168,7 @@ describe('fastify', () => {
       assert.deepStrictEqual(span.attributes, {
         'fastify.type': 'request_handler',
         'fastify.name': 'namedHandler',
-        'plugin.name': 'fastify-express',
+        'plugin.name': 'fastify -> @fastify/express',
         [SemanticAttributes.HTTP_ROUTE]: '/test',
       });
       assert.strictEqual(span.name, 'request handler - namedHandler');
@@ -232,7 +232,7 @@ describe('fastify', () => {
         assert.strictEqual(span.name, 'middleware - runConnect');
         assert.deepStrictEqual(span.attributes, {
           'fastify.type': 'middleware',
-          'plugin.name': 'fastify-express',
+          'plugin.name': 'fastify -> @fastify/express',
           'hook.name': 'onRequest',
         });
 
@@ -248,7 +248,7 @@ describe('fastify', () => {
         assert.strictEqual(span.name, 'middleware - enhanceRequest');
         assert.deepStrictEqual(span.attributes, {
           'fastify.type': 'middleware',
-          'plugin.name': 'fastify-express',
+          'plugin.name': 'fastify -> @fastify/express',
           'hook.name': 'onRequest',
         });
 
@@ -338,12 +338,16 @@ describe('fastify', () => {
 
           // done was not yet called from the hook, so it should not end the span
           const preDoneSpans = getSpans().filter(
-            s => !s.attributes[AttributeNames.PLUGIN_NAME]
+            s =>
+              !s.attributes[AttributeNames.PLUGIN_NAME] ||
+              s.attributes[AttributeNames.PLUGIN_NAME] === 'fastify'
           );
           assert.strictEqual(preDoneSpans.length, 0);
           hookDone!();
           const postDoneSpans = getSpans().filter(
-            s => !s.attributes[AttributeNames.PLUGIN_NAME]
+            s =>
+              !s.attributes[AttributeNames.PLUGIN_NAME] ||
+              s.attributes[AttributeNames.PLUGIN_NAME] === 'fastify'
           );
           assert.strictEqual(postDoneSpans.length, 1);
         });
@@ -367,7 +371,9 @@ describe('fastify', () => {
           await startServer();
           await httpRequest.get(`http://localhost:${PORT}/test`);
           const spans = getSpans().filter(
-            s => !s.attributes[AttributeNames.PLUGIN_NAME]
+            s =>
+              !s.attributes[AttributeNames.PLUGIN_NAME] ||
+              s.attributes[AttributeNames.PLUGIN_NAME] === 'fastify'
           );
           assert.strictEqual(spans.length, 1);
         });