diff --git a/dlls/wined3d/directx.c b/dlls/wined3d/directx.c
index e0e6880aa4b..c4c272a343a 100644
--- a/dlls/wined3d/directx.c
+++ b/dlls/wined3d/directx.c
@@ -3124,7 +3124,7 @@ static BOOL CheckTextureCapability(struct wined3d_adapter *adapter,
          *
          * With Shader Model 3.0 capable cards Instancing 'just works' in Windows.
          */
-        case WINEMAKEFOURCC('I','N','S','T'):
+        case WINED3DFMT_INST:
             TRACE("ATI Instancing check hack\n");
             if (gl_info->supported[ARB_VERTEX_PROGRAM] || gl_info->supported[ARB_VERTEX_SHADER])
             {
diff --git a/include/wine/wined3d.idl b/include/wine/wined3d.idl
index 16ae4433991..c91437a5a77 100644
--- a/include/wine/wined3d.idl
+++ b/include/wine/wined3d.idl
@@ -266,6 +266,7 @@ typedef enum _WINED3DFORMAT
     WINED3DFMT_G8R8_G8B8                    = 0x42475247, /* GRGB */
     WINED3DFMT_R8G8_B8G8                    = 0x47424752, /* RGBG */
     WINED3DFMT_ATI2N                        = 0x32495441, /* ATI2 */
+    WINED3DFMT_INST                         = 0x54534e49, /* INST */
     WINED3DFMT_NVHU                         = 0x5548564e, /* NVHU */
     WINED3DFMT_NVHS                         = 0x5348564e, /* NVHS */