diff --git a/src/mac/carbon/uma.cpp b/src/mac/carbon/uma.cpp
index 2ca3e8cc2b..4fe99c0e6a 100644
--- a/src/mac/carbon/uma.cpp
+++ b/src/mac/carbon/uma.cpp
@@ -379,7 +379,7 @@ GrafPtr		UMAGetWindowPort( WindowRef inWindowRef )
 {
 	wxASSERT( inWindowRef != NULL ) ;
 #if TARGET_CARBON 
-	return GetWindowPort( inWindowRef ) ; 
+	return (GrafPtr) GetWindowPort( inWindowRef ) ; 
 #else
 	return (GrafPtr) inWindowRef ;
 #endif
diff --git a/src/mac/uma.cpp b/src/mac/uma.cpp
index 2ca3e8cc2b..4fe99c0e6a 100644
--- a/src/mac/uma.cpp
+++ b/src/mac/uma.cpp
@@ -379,7 +379,7 @@ GrafPtr		UMAGetWindowPort( WindowRef inWindowRef )
 {
 	wxASSERT( inWindowRef != NULL ) ;
 #if TARGET_CARBON 
-	return GetWindowPort( inWindowRef ) ; 
+	return (GrafPtr) GetWindowPort( inWindowRef ) ; 
 #else
 	return (GrafPtr) inWindowRef ;
 #endif