diff --git a/reactos/subsystems/win32/win32k/eng/bitblt.c b/reactos/subsystems/win32/win32k/eng/bitblt.c
index ade750056b7..5d4ffe06bf1 100644
--- a/reactos/subsystems/win32/win32k/eng/bitblt.c
+++ b/reactos/subsystems/win32/win32k/eng/bitblt.c
@@ -955,7 +955,7 @@ NtGdiEngAlphaBlend(IN SURFOBJ *Dest,
         ProbeForRead(upDestRect, sizeof(RECTL), 1);
         RtlCopyMemory(&DestRect,upDestRect, sizeof(RECTL));
         ProbeForRead(upSourceRect, sizeof(RECTL), 1);
-        RtlCopyMemory(&Source, upSourceRect, sizeof(RECTL));
+        RtlCopyMemory(&SourceRect, upSourceRect, sizeof(RECTL));
 
     }
     _SEH_HANDLE