diff --git a/widget/src/qt/nsClipboard.cpp b/widget/src/qt/nsClipboard.cpp
index bda43aec0c1a..40f84f0b475f 100644
--- a/widget/src/qt/nsClipboard.cpp
+++ b/widget/src/qt/nsClipboard.cpp
@@ -242,6 +242,7 @@ nsClipboard::SetNativeClipboardData( nsITransferable *aTransferable,
                     QByteArray data ((const char *)primitive_data, len);
                     // Add data to the mimeData
                     mimeData->setData(flavorStr.get(), data);
+                    nsMemory::Free(primitive_data);
                 }
             }
         }