diff --git a/src/mesa/drivers/windows/gdi/wgl.c b/src/mesa/drivers/windows/gdi/wgl.c
index 49b4ddbd1f9..fb23d210db7 100644
--- a/src/mesa/drivers/windows/gdi/wgl.c
+++ b/src/mesa/drivers/windows/gdi/wgl.c
@@ -339,7 +339,7 @@ WINGDIAPI int GLAPIENTRY wglGetPixelFormat(HDC hdc)
 }
 
 WINGDIAPI BOOL GLAPIENTRY wglSetPixelFormat(HDC hdc,int iPixelFormat,
-					    PIXELFORMATDESCRIPTOR *ppfd)
+					    const PIXELFORMATDESCRIPTOR *ppfd)
 {
     (void) hdc;