diff --git a/fetch.js b/fetch.js
index c1ff6df..9f1f569 100644
--- a/fetch.js
+++ b/fetch.js
@@ -178,8 +178,12 @@
       } else if (!body) {
         this._bodyText = ''
       } else if (support.arrayBuffer && ArrayBuffer.prototype.isPrototypeOf(body)) {
-        // Only support ArrayBuffers for POST method.
-        // Receiving ArrayBuffers happens via Blobs, instead.
+        if (body.slice) {
+          this._bodyArrayBuffer = new Uint8Array(body.slice(0))
+        } else {
+          this._bodyArrayBuffer = new Uint8Array(body.byteLength)
+          this._bodyArrayBuffer.set(new Uint8Array(body))
+        }
       } else {
         throw new Error('unsupported BodyInit type')
       }
@@ -211,10 +215,6 @@
         }
       }
 
-      this.arrayBuffer = function() {
-        return this.blob().then(readBlobAsArrayBuffer)
-      }
-
       this.text = function() {
         var rejected = consumed(this)
         if (rejected) {
@@ -231,8 +231,17 @@
       }
     } else {
       this.text = function() {
-        var rejected = consumed(this)
-        return rejected ? rejected : Promise.resolve(this._bodyText)
+        return consumed(this) || Promise.resolve(this._bodyText)
+      }
+    }
+
+    if (support.arrayBuffer) {
+      this.arrayBuffer = function() {
+        if (this._bodyArrayBuffer) {
+          return consumed(this) || Promise.resolve(this._bodyArrayBuffer.buffer)
+        } else {
+          return this.blob().then(readBlobAsArrayBuffer)
+        }
       }
     }
 
diff --git a/test/test.js b/test/test.js
index d5fb33f..fed12b4 100644
--- a/test/test.js
+++ b/test/test.js
@@ -444,6 +444,28 @@ suite('Request', function() {
       })
     })
 
+    featureDependent(suite, support.arrayBuffer, 'type ArrayBuffer', function() {
+      test('consume as array buffer', function() {
+        var text = 'name=Hubot'
+
+        var buf = new ArrayBuffer(text.length)
+        var view = new Uint8Array(buf)
+
+        for(var i = 0; i < text.length; i++) {
+          view[i] = text.charCodeAt(i)
+        }
+
+        var request = new Request('', {method: 'POST', body: buf})
+        return request.arrayBuffer().then(function(buffer) {
+          var bufView = new Uint8Array(buffer)
+          assert.equal(bufView.byteLength, view.length)
+          for(var i = 0; i < bufView.length; i++) {
+            assert.equal(bufView[i], view[i])
+          }
+        })
+      })
+    })
+
     suite('type USVString', function() {
       test('consume as text', function() {
         var request = new Request('', {method: 'POST', body: 'hello'})
@@ -482,6 +504,28 @@ suite('Response', function() {
       })
     })
 
+    featureDependent(suite, support.arrayBuffer, 'type ArrayBuffer', function() {
+      test('consume as array buffer', function() {
+        var text = 'name=Hubot'
+
+        var buf = new ArrayBuffer(text.length)
+        var view = new Uint8Array(buf)
+
+        for(var i = 0; i < text.length; i++) {
+          view[i] = text.charCodeAt(i)
+        }
+
+        var response = new Response(buf)
+        return response.arrayBuffer().then(function(buffer) {
+          var bufView = new Uint8Array(buffer)
+          assert.equal(bufView.byteLength, view.byteLength)
+          for(var i = 0; i < bufView.byteLength; i++) {
+            assert.equal(bufView[i], view[i])
+          }
+        })
+      })
+    })
+
     suite('type USVString', function() {
       test('consume as text', function() {
         var response = new Response('hello')