diff --git a/dom/indexedDB/IDBObjectStore.cpp b/dom/indexedDB/IDBObjectStore.cpp
index 181a67aa1e0..65895e3dadb 100644
--- a/dom/indexedDB/IDBObjectStore.cpp
+++ b/dom/indexedDB/IDBObjectStore.cpp
@@ -428,7 +428,9 @@ GetKeyFromValue(JSContext* aCx,
                 Key& aKey)
 {
   NS_ASSERTION(aCx, "Null pointer!");
-  NS_ASSERTION(!JSVAL_IS_PRIMITIVE(aVal), "Why are we here!?");
+  // aVal can be primitive iff the key path is empty.
+  NS_ASSERTION(!JSVAL_IS_PRIMITIVE(aVal) || aKeyPath.IsEmpty(),
+               "Why are we here!?");
   NS_ASSERTION(IDBObjectStore::IsValidKeyPath(aCx, aKeyPath),
                "This will explode!");
 
@@ -580,7 +582,6 @@ IDBObjectStore::GetKeyPathValueFromStructuredData(const PRUint8* aData,
 {
   NS_ASSERTION(aData, "Null pointer!");
   NS_ASSERTION(aDataLength, "Empty data!");
-  NS_ASSERTION(!aKeyPath.IsEmpty(), "Empty keyPath!");
   NS_ASSERTION(aCx, "Null pointer!");
 
   JSAutoRequest ar(aCx);
@@ -592,7 +593,7 @@ IDBObjectStore::GetKeyPathValueFromStructuredData(const PRUint8* aData,
     return NS_ERROR_DOM_DATA_CLONE_ERR;
   }
 
-  if (JSVAL_IS_PRIMITIVE(clone)) {
+  if (JSVAL_IS_PRIMITIVE(clone) && !aKeyPath.IsEmpty()) {
     // This isn't an object, so just leave the key unset.
     aValue.Unset();
     return NS_OK;
@@ -614,7 +615,7 @@ IDBObjectStore::GetIndexUpdateInfo(ObjectStoreInfo* aObjectStoreInfo,
   JSObject* cloneObj = nsnull;
 
   PRUint32 count = aObjectStoreInfo->indexes.Length();
-  if (count && !JSVAL_IS_PRIMITIVE(aObject)) {
+  if (count) {
     if (!aUpdateInfoArray.SetCapacity(count)) {
       NS_ERROR("Out of memory!");
       return NS_ERROR_OUT_OF_MEMORY;
@@ -623,6 +624,10 @@ IDBObjectStore::GetIndexUpdateInfo(ObjectStoreInfo* aObjectStoreInfo,
     for (PRUint32 indexesIndex = 0; indexesIndex < count; indexesIndex++) {
       const IndexInfo& indexInfo = aObjectStoreInfo->indexes[indexesIndex];
 
+      if (JSVAL_IS_PRIMITIVE(aObject) && !indexInfo.keyPath.IsEmpty()) {
+        continue;
+      }
+
       Key value;
       nsresult rv = GetKeyFromValue(aCx, aObject, indexInfo.keyPath, value);
       NS_ENSURE_SUCCESS(rv, rv);
@@ -1334,10 +1339,6 @@ IDBObjectStore::CreateIndex(const nsAString& aName,
 {
   NS_PRECONDITION(NS_IsMainThread(), "Wrong thread!");
 
-  if (aKeyPath.IsEmpty()) {
-    return NS_ERROR_DOM_INDEXEDDB_NON_TRANSIENT_ERR;
-  }
-
   if (!IsValidKeyPath(aCx, aKeyPath)) {
     return NS_ERROR_DOM_SYNTAX_ERR;
   }
diff --git a/dom/indexedDB/test/Makefile.in b/dom/indexedDB/test/Makefile.in
index 719b315929d..3e5c0a24495 100644
--- a/dom/indexedDB/test/Makefile.in
+++ b/dom/indexedDB/test/Makefile.in
@@ -75,6 +75,7 @@ TEST_FILES = \
   test_exceptions_in_success_events.html \
   test_getAll.html \
   test_global_data.html \
+  test_index_empty_keyPath.html \
   test_index_getAll.html \
   test_index_getAllObjects.html \
   test_index_object_cursors.html \
diff --git a/dom/indexedDB/test/test_index_empty_keyPath.html b/dom/indexedDB/test/test_index_empty_keyPath.html
new file mode 100644
index 00000000000..f9e7e2bad24
--- /dev/null
+++ b/dom/indexedDB/test/test_index_empty_keyPath.html
@@ -0,0 +1,95 @@
+<!--
+  Any copyright is dedicated to the Public Domain.
+  http://creativecommons.org/publicdomain/zero/1.0/
+-->
+<html>
+<head>
+  <title>Indexed Database Property Test</title>
+
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css"/>
+
+  <script type="text/javascript;version=1.7">
+    function testSteps()
+    {
+      const name = window.location.pathname;
+
+      const objectStoreData = [
+        { key: "1", value: "foo" },
+        { key: "2", value: "bar" },
+        { key: "3", value: "baz" }
+      ];
+
+      let request = mozIndexedDB.open(name, 1);
+      request.onerror = errorHandler;
+      request.onupgradeneeded = grabEventAndContinueHandler;
+      request.onsuccess = grabEventAndContinueHandler;
+      let event = yield; // upgradeneeded
+
+      let db = event.target.result;
+
+      let objectStore = db.createObjectStore("data", { keyPath: null });
+
+      // First, add all our data to the object store.
+      let addedData = 0;
+      for (let i in objectStoreData) {
+        request = objectStore.add(objectStoreData[i].value,
+                                  objectStoreData[i].key);
+        request.onerror = errorHandler;
+        request.onsuccess = function(event) {
+          if (++addedData == objectStoreData.length) {
+            testGenerator.send(event);
+          }
+        }
+      }
+      event = yield; // testGenerator.send
+
+      // Now create the index.
+      objectStore.createIndex("set", "", { unique: true });
+      yield; // success
+
+      let trans = db.transaction("data", IDBTransaction.READ_WRITE);
+      objectStore = trans.objectStore("data");
+      index = objectStore.index("set");
+
+      let request = index.get("bar");
+      request.onerror = errorHandler;
+      request.onsuccess = grabEventAndContinueHandler;
+      
+      let event = yield;
+
+      is(event.target.result, "bar", "Got correct result");
+
+      let request = objectStore.add("foopy", 4);
+      request.onerror = errorHandler;
+      request.onsuccess = grabEventAndContinueHandler;
+
+      yield;
+
+      let request = index.get("foopy");
+      request.onerror = errorHandler;
+      request.onsuccess = grabEventAndContinueHandler;
+      
+      let event = yield;
+
+      is(event.target.result, "foopy", "Got correct result");
+
+      let request = objectStore.add("foopy", 5);
+      request.onerror = new ExpectError(IDBDatabaseException.CONSTRAINT_ERR);
+      request.onsuccess = unexpectedSuccessHandler;
+
+      trans.oncomplete = grabEventAndContinueHandler;
+
+      yield;
+      yield;
+
+      finishTest();
+      yield;
+    }
+  </script>
+  <script type="text/javascript;version=1.7" src="helpers.js"></script>
+</head>
+
+<body onload="runTest();"></body>
+
+</html>
