diff --git a/embedding/browser/webBrowser/nsCommandHandler.cpp b/embedding/browser/webBrowser/nsCommandHandler.cpp
index fb004e96fad8..db5ada47a309 100644
--- a/embedding/browser/webBrowser/nsCommandHandler.cpp
+++ b/embedding/browser/webBrowser/nsCommandHandler.cpp
@@ -8,7 +8,7 @@
 #include "nsWebBrowser.h"
 #include "nsDocShellTreeOwner.h"
 
-#include "nsIAllocator.h"
+#include "nsMemory.h"
 #include "nsPIDOMWindow.h"
 
 nsCommandHandler::nsCommandHandler() :
@@ -118,7 +118,7 @@ NS_IMETHODIMP nsCommandHandler::Exec(const char *aCommand, const char *aStatus,
 
     // Return an empty string
     const char szEmpty[] = "";
-    *aResult = (char *) nsAllocator::Clone(szEmpty, sizeof(szEmpty));
+    *aResult = (char *) nsMemory::Clone(szEmpty, sizeof(szEmpty));
 
     return NS_OK;
 }
@@ -141,7 +141,7 @@ NS_IMETHODIMP nsCommandHandler::Query(const char *aCommand, const char *aStatus,
 
     // Return an empty string
     const char szEmpty[] = "";
-    *aResult = (char *) nsAllocator::Clone(szEmpty, sizeof(szEmpty));
+    *aResult = (char *) nsMemory::Clone(szEmpty, sizeof(szEmpty));
 
     return NS_OK;
 }
diff --git a/xpcom/base/moz.build b/xpcom/base/moz.build
index 6ce9dd576ee5..6c32c53567d3 100644
--- a/xpcom/base/moz.build
+++ b/xpcom/base/moz.build
@@ -49,7 +49,6 @@ EXPORTS += [
     'nsDebugImpl.h',
     'nsError.h',
     'nsGZFileWriter.h',
-    'nsIAllocator.h',
     'nsIID.h',
     'nsInterfaceRequestorAgg.h',
     'nsISizeOf.h',
diff --git a/xpcom/base/nsAllocator.h b/xpcom/base/nsAllocator.h
index cae01c7e7942..2be14e5625cb 100644
--- a/xpcom/base/nsAllocator.h
+++ b/xpcom/base/nsAllocator.h
@@ -10,7 +10,6 @@
 #ifndef nsAllocator_h__
 #define nsAllocator_h__
 
-#include "nsIAllocator.h"
 #include "nsAgg.h"
 #include "nsIFactory.h"
 
diff --git a/xpcom/base/nsIAllocator.h b/xpcom/base/nsIAllocator.h
deleted file mode 100644
index b68498106f8b..000000000000
--- a/xpcom/base/nsIAllocator.h
+++ /dev/null
@@ -1,23 +0,0 @@
-/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/**
- * XXX This file is obsolete. Use nsIMemory.idl or nsMemory.h instead.
- */
-
-#ifndef nsIAllocator_h___
-#define nsIAllocator_h___
-
-#include "nsMemory.h"
-
-#define nsIAllocator            nsIMemory
-#define nsAllocator             nsMemory
-#define GetGlobalAllocator      GetGlobalMemoryService
-
-#define NS_IALLOCATOR_IID       NS_GET_IID(nsIMemory)
-#define NS_ALLOCATOR_CONTRACTID NS_MEMORY_CONTRACTID
-#define NS_ALLOCATOR_CID        NS_MEMORY_CID
-
-#endif /* nsIAllocator_h___ */