diff --git a/mozilla/content/base/src/nsDocument.cpp b/mozilla/content/base/src/nsDocument.cpp
index dbea7ffa105..7b63ec134ef 100644
--- a/mozilla/content/base/src/nsDocument.cpp
+++ b/mozilla/content/base/src/nsDocument.cpp
@@ -1498,7 +1498,6 @@ void nsDocument::AddStyleSheet(nsIStyleSheet* aSheet, PRUint32 aFlags)
 {
   NS_PRECONDITION(nsnull != aSheet, "null arg");
   InternalAddStyleSheet(aSheet, aFlags);
-  NS_ADDREF(aSheet);
   aSheet->SetOwningDocument(this);
 
   PRBool enabled = PR_TRUE;