diff --git a/xpcom/ds/nsICollection.h b/xpcom/ds/nsICollection.h
new file mode 100644
index 000000000000..658c6ed15ac0
--- /dev/null
+++ b/xpcom/ds/nsICollection.h
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * The contents of this file are subject to the Netscape Public License
+ * Version 1.0 (the "NPL"); you may not use this file except in
+ * compliance with the NPL.  You may obtain a copy of the NPL at
+ * http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the NPL is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
+ * for the specifzic language governing rights and limitations under the
+ * NPL.
+ *
+ * The Initial Developer of this code under the NPL is Netscape
+ * Communications Corporation.  Portions created by Netscape are
+ * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
+ * Reserved.
+ */
+#ifndef nsICollection_h___
+#define nsICollection_h___
+
+#include "nsISupports.h"
+
+// IID for the nsICollection interface
+#define NS_ICOLLECTION_IID      \
+{ 0xaeca730, 0x835b, 0x11d2, \
+  { 0x8f, 0x30, 0x0, 0x60, 0x8, 0x31, 0x1, 0x94 } }
+
+
+// IID for the nsICollection Factort interface
+#define NS_ICOLLECTIONFACTORY_IID      \
+{ 0xf8052641, 0x8768, 0x11d2, \
+  { 0x8f, 0x39, 0x0, 0x60, 0x8, 0x31, 0x1, 0x94 } }
+
+//----------------------------------------------------------------------
+
+/** nsICollection Interface
+ *  this may be ordered or not. a list or array, the implementation is opaque
+ */
+class nsICollection : public nsISupports {
+public:
+
+
+  /** AddItem will take an ISupports and keep track of it 
+   *  @param aItem is the Item to be added WILL BE ADDREFFED
+   */
+  virtual nsresult AddItem(nsISupports *aItem)=0;
+
+  /** RemoveItem will take an nsISupports and remove it from the collection
+   *  @param aItem is the item to be removed  WILL BE RELEASED
+   */
+  virtual nsresult RemoveItem(nsISupports *aItem)=0;
+
+  /** Clear will clear all items from list
+   */
+  virtual nsresult Clear()=0;
+};
+
+
+#endif /* nsICollection_h___ */
+
diff --git a/xpcom/public/nsICollection.h b/xpcom/public/nsICollection.h
new file mode 100644
index 000000000000..658c6ed15ac0
--- /dev/null
+++ b/xpcom/public/nsICollection.h
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ *
+ * The contents of this file are subject to the Netscape Public License
+ * Version 1.0 (the "NPL"); you may not use this file except in
+ * compliance with the NPL.  You may obtain a copy of the NPL at
+ * http://www.mozilla.org/NPL/
+ *
+ * Software distributed under the NPL is distributed on an "AS IS" basis,
+ * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the NPL
+ * for the specifzic language governing rights and limitations under the
+ * NPL.
+ *
+ * The Initial Developer of this code under the NPL is Netscape
+ * Communications Corporation.  Portions created by Netscape are
+ * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
+ * Reserved.
+ */
+#ifndef nsICollection_h___
+#define nsICollection_h___
+
+#include "nsISupports.h"
+
+// IID for the nsICollection interface
+#define NS_ICOLLECTION_IID      \
+{ 0xaeca730, 0x835b, 0x11d2, \
+  { 0x8f, 0x30, 0x0, 0x60, 0x8, 0x31, 0x1, 0x94 } }
+
+
+// IID for the nsICollection Factort interface
+#define NS_ICOLLECTIONFACTORY_IID      \
+{ 0xf8052641, 0x8768, 0x11d2, \
+  { 0x8f, 0x39, 0x0, 0x60, 0x8, 0x31, 0x1, 0x94 } }
+
+//----------------------------------------------------------------------
+
+/** nsICollection Interface
+ *  this may be ordered or not. a list or array, the implementation is opaque
+ */
+class nsICollection : public nsISupports {
+public:
+
+
+  /** AddItem will take an ISupports and keep track of it 
+   *  @param aItem is the Item to be added WILL BE ADDREFFED
+   */
+  virtual nsresult AddItem(nsISupports *aItem)=0;
+
+  /** RemoveItem will take an nsISupports and remove it from the collection
+   *  @param aItem is the item to be removed  WILL BE RELEASED
+   */
+  virtual nsresult RemoveItem(nsISupports *aItem)=0;
+
+  /** Clear will clear all items from list
+   */
+  virtual nsresult Clear()=0;
+};
+
+
+#endif /* nsICollection_h___ */
+