diff --git a/src/osx/carbon/graphics.cpp b/src/osx/carbon/graphics.cpp
index 3a5306d1bb..549b201300 100644
--- a/src/osx/carbon/graphics.cpp
+++ b/src/osx/carbon/graphics.cpp
@@ -165,6 +165,7 @@ CGColorRef wxMacCreateCGColor( const wxColour& col )
     }
 
 #endif
+    wxASSERT(retval != NULL);
     return retval;
 }