diff --git a/dlls/gdi32/mapping.c b/dlls/gdi32/mapping.c
index e199dd3cd39..35bb1ea0f81 100644
--- a/dlls/gdi32/mapping.c
+++ b/dlls/gdi32/mapping.c
@@ -424,7 +424,7 @@ BOOL WINAPI ScaleViewportExtEx( HDC hdc, INT xNum, INT xDenom,
     }
     if ((dc->MapMode != MM_ISOTROPIC) && (dc->MapMode != MM_ANISOTROPIC))
 	goto done;
-    if (!xNum || !xDenom || !xNum || !yDenom)
+    if (!xNum || !xDenom || !yNum || !yDenom)
     {
         ret = FALSE;
         goto done;