diff --git a/reactos/include/win32k/ntgdibad.h b/reactos/include/win32k/ntgdibad.h
index edc23be94b5..f44e0a4ee76 100644
--- a/reactos/include/win32k/ntgdibad.h
+++ b/reactos/include/win32k/ntgdibad.h
@@ -188,14 +188,6 @@ NtGdiArcTo(HDC  hDC,
                 int  XRadial2,
                 int  YRadial2);
 
-/* Does not exist */
-BOOL
-STDCALL
-NtGdiCheckColorsInGamut(HDC  hDC,
-                             LPVOID  RGBTriples,
-                             LPVOID  Buffer,
-                             UINT  Count);
-
 /* Use NtGdiArcInternal with GdiTypeChord */
 BOOL
 STDCALL
diff --git a/reactos/subsys/win32k/objects/icm.c b/reactos/subsys/win32k/objects/icm.c
index ae3008cba86..e49c28894ce 100644
--- a/reactos/subsys/win32k/objects/icm.c
+++ b/reactos/subsys/win32k/objects/icm.c
@@ -23,17 +23,6 @@
 #define NDEBUG
 #include <debug.h>
 
-BOOL
-STDCALL
-NtGdiCheckColorsInGamut(HDC  hDC,
-                             LPVOID  RGBTriples,
-                             LPVOID  Buffer,
-                             UINT  Count)
-{
-  UNIMPLEMENTED;
-  return FALSE;
-}
-
 BOOL
 STDCALL
 NtGdiColorMatchToTarget(HDC  hDC,
diff --git a/reactos/tools/nci/w32ksvc.db b/reactos/tools/nci/w32ksvc.db
index 25fd8712ba9..6991b26892e 100644
--- a/reactos/tools/nci/w32ksvc.db
+++ b/reactos/tools/nci/w32ksvc.db
@@ -10,7 +10,6 @@ NtGdiArcTo				9
 NtGdiBeginPath				1
 NtGdiBitBlt				11
 NtGdiCancelDC				1
-NtGdiCheckColorsInGamut			4
 NtGdiChord				9
 NtGdiCloseEnhMetaFile			1
 NtGdiCloseFigure			1