diff --git a/src/main/java/org/takes/rs/RsWithBody.java b/src/main/java/org/takes/rs/RsWithBody.java
index 846ed6fa8..3c201ebb0 100644
--- a/src/main/java/org/takes/rs/RsWithBody.java
+++ b/src/main/java/org/takes/rs/RsWithBody.java
@@ -27,6 +27,9 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.net.URL;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
 import lombok.EqualsAndHashCode;
 import org.takes.Response;
 
@@ -42,6 +45,11 @@
 @EqualsAndHashCode(callSuper = true)
 public final class RsWithBody extends RsWrap {
 
+    /**
+     * String for content lenght key:value.
+     */
+    private static final String CONT_LGTH = "Content-Length:%s";
+
     /**
      * Ctor.
      * @param body Body
@@ -93,7 +101,16 @@ public RsWithBody(final Response res, final URL url) {
             new Response() {
                 @Override
                 public Iterable<String> head() throws IOException {
-                    return res.head();
+                    final List<String> headerAttr = getHeadAttributes(
+                            res.head()
+                    );
+                    headerAttr.add(
+                            String.format(
+                                    CONT_LGTH,
+                                    url.openStream().available()
+                        )
+                    );
+                    return headerAttr;
                 }
                 @Override
                 public InputStream body() throws IOException {
@@ -113,7 +130,15 @@ public RsWithBody(final Response res, final byte[] body) {
             new Response() {
                 @Override
                 public Iterable<String> head() throws IOException {
-                    return res.head();
+                    final List<String> headerAttr = getHeadAttributes(
+                            res.head()
+                    );
+                    headerAttr.add(
+                            String.format(
+                                    CONT_LGTH, body.length
+                        )
+                    );
+                    return headerAttr;
                 }
                 @Override
                 public InputStream body() {
@@ -133,7 +158,15 @@ public RsWithBody(final Response res, final InputStream body) {
             new Response() {
                 @Override
                 public Iterable<String> head() throws IOException {
-                    return res.head();
+                    final List<String> headerAttr = getHeadAttributes(
+                            res.head()
+                    );
+                    headerAttr.add(
+                            String.format(
+                                    CONT_LGTH, body.available()
+                        )
+                    );
+                    return headerAttr;
                 }
                 @Override
                 public InputStream body() {
@@ -143,4 +176,19 @@ public InputStream body() {
         );
     }
 
+    /**
+     * Forms a list with header attributes from response.
+     * @param head Response head
+     * @return List of header attributes
+     */
+    private static List<String> getHeadAttributes(final Iterable<String> head) {
+        final Iterator<String> itr = head.iterator();
+        // @checkstyle ConditionalRegexpMultilineCheck (1 line)
+        final List<String> headerAttrs = new ArrayList<String>();
+        while (itr.hasNext()) {
+            headerAttrs.add(itr.next());
+        }
+        return headerAttrs;
+    }
+
 }
diff --git a/src/test/java/org/takes/facets/fork/TkForkTest.java b/src/test/java/org/takes/facets/fork/TkForkTest.java
index 88b329f69..ea33682fe 100644
--- a/src/test/java/org/takes/facets/fork/TkForkTest.java
+++ b/src/test/java/org/takes/facets/fork/TkForkTest.java
@@ -55,6 +55,7 @@ public void dispatchesByRegularExpression() throws IOException {
             Matchers.equalTo(
                 Joiner.on("\r\n").join(
                     "HTTP/1.1 200 OK",
+                    String.format("Content-Length:%s", body.length()),
                     "Content-Type: text/plain",
                     "",
                     body
diff --git a/src/test/java/org/takes/rs/RsTextTest.java b/src/test/java/org/takes/rs/RsTextTest.java
index 72d990e81..f2c0826c7 100644
--- a/src/test/java/org/takes/rs/RsTextTest.java
+++ b/src/test/java/org/takes/rs/RsTextTest.java
@@ -49,6 +49,7 @@ public void makesPlainTextResponse() throws IOException {
             Matchers.equalTo(
                 Joiner.on("\r\n").join(
                     "HTTP/1.1 200 OK",
+                    String.format("Content-Length:%s", body.length()),
                     "Content-Type: text/plain",
                     "",
                     body
diff --git a/src/test/java/org/takes/tk/TkHTMLTest.java b/src/test/java/org/takes/tk/TkHTMLTest.java
index 4773e8ee0..3167eba0f 100644
--- a/src/test/java/org/takes/tk/TkHTMLTest.java
+++ b/src/test/java/org/takes/tk/TkHTMLTest.java
@@ -52,6 +52,7 @@ public void createsTextResponse() throws IOException {
             Matchers.equalTo(
                 Joiner.on("\r\n").join(
                     "HTTP/1.1 200 OK",
+                    String.format("Content-Length:%s", body.length()),
                     "Content-Type: text/html",
                     "",
                     body
diff --git a/src/test/java/org/takes/tk/TkTextTest.java b/src/test/java/org/takes/tk/TkTextTest.java
index f22228220..49ddf686a 100644
--- a/src/test/java/org/takes/tk/TkTextTest.java
+++ b/src/test/java/org/takes/tk/TkTextTest.java
@@ -52,6 +52,7 @@ public void createsTextResponse() throws IOException {
             Matchers.equalTo(
                 Joiner.on("\r\n").join(
                     "HTTP/1.1 200 OK",
+                    String.format("Content-Length:%s", body.length()),
                     "Content-Type: text/plain",
                     "",
                     body