diff --git a/content/xslt/src/xpath/nsXPathExpression.cpp b/content/xslt/src/xpath/nsXPathExpression.cpp
index ddc4cbc16c5..21c39e78958 100644
--- a/content/xslt/src/xpath/nsXPathExpression.cpp
+++ b/content/xslt/src/xpath/nsXPathExpression.cpp
@@ -49,9 +49,13 @@
 #include "txURIUtils.h"
 #include "txXPathTreeWalker.h"
 
-NS_IMPL_ADDREF(nsXPathExpression)
-NS_IMPL_RELEASE(nsXPathExpression)
-NS_INTERFACE_MAP_BEGIN(nsXPathExpression)
+NS_IMPL_CYCLE_COLLECTION_1(nsXPathExpression, mDocument)
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF_AMBIGUOUS(nsXPathExpression,
+                                          nsIDOMXPathExpression)
+NS_IMPL_CYCLE_COLLECTING_RELEASE_AMBIGUOUS(nsXPathExpression,
+                                           nsIDOMXPathExpression)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsXPathExpression)
   NS_INTERFACE_MAP_ENTRY(nsIDOMXPathExpression)
   NS_INTERFACE_MAP_ENTRY(nsIDOMNSXPathExpression)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMXPathExpression)
diff --git a/content/xslt/src/xpath/nsXPathExpression.h b/content/xslt/src/xpath/nsXPathExpression.h
index e1b29cae779..7eeef3e8694 100644
--- a/content/xslt/src/xpath/nsXPathExpression.h
+++ b/content/xslt/src/xpath/nsXPathExpression.h
@@ -44,6 +44,7 @@
 #include "txIXPathContext.h"
 #include "txResultRecycler.h"
 #include "nsAutoPtr.h"
+#include "nsCycleCollectionParticipant.h"
 
 class Expr;
 class txXPathNode;
@@ -59,7 +60,9 @@ public:
                       nsIDOMDocument *aDocument);
 
     // nsISupports interface
-    NS_DECL_ISUPPORTS
+    NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+    NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsXPathExpression,
+                                             nsIDOMXPathExpression)
 
     // nsIDOMXPathExpression interface
     NS_DECL_NSIDOMXPATHEXPRESSION
diff --git a/content/xslt/src/xpath/nsXPathNSResolver.cpp b/content/xslt/src/xpath/nsXPathNSResolver.cpp
index 8fee8ae7068..a8740c4db20 100644
--- a/content/xslt/src/xpath/nsXPathNSResolver.cpp
+++ b/content/xslt/src/xpath/nsXPathNSResolver.cpp
@@ -41,9 +41,11 @@
 #include "nsDOMString.h"
 #include "nsContentUtils.h"
 
-NS_IMPL_ADDREF(nsXPathNSResolver)
-NS_IMPL_RELEASE(nsXPathNSResolver)
-NS_INTERFACE_MAP_BEGIN(nsXPathNSResolver)
+NS_IMPL_CYCLE_COLLECTION_1(nsXPathNSResolver, mNode)
+
+NS_IMPL_CYCLE_COLLECTING_ADDREF(nsXPathNSResolver)
+NS_IMPL_CYCLE_COLLECTING_RELEASE(nsXPathNSResolver)
+NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(nsXPathNSResolver)
   NS_INTERFACE_MAP_ENTRY(nsIDOMXPathNSResolver)
   NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIDOMXPathNSResolver)
   NS_INTERFACE_MAP_ENTRY_CONTENT_CLASSINFO(XPathNSResolver)
diff --git a/content/xslt/src/xpath/nsXPathNSResolver.h b/content/xslt/src/xpath/nsXPathNSResolver.h
index 14004d856b2..6756643c613 100644
--- a/content/xslt/src/xpath/nsXPathNSResolver.h
+++ b/content/xslt/src/xpath/nsXPathNSResolver.h
@@ -43,6 +43,7 @@
 #include "nsIDOMNode.h"
 #include "nsIDOM3Node.h"
 #include "nsCOMPtr.h"
+#include "nsCycleCollectionParticipant.h"
 
 /**
  * A class for evaluating an XPath expression string
@@ -53,7 +54,8 @@ public:
     nsXPathNSResolver(nsIDOMNode* aNode);
 
     // nsISupports interface
-    NS_DECL_ISUPPORTS
+    NS_DECL_CYCLE_COLLECTING_ISUPPORTS
+    NS_DECL_CYCLE_COLLECTION_CLASS(nsXPathNSResolver)
 
     // nsIDOMXPathNSResolver interface
     NS_DECL_NSIDOMXPATHNSRESOLVER