diff --git a/SDL2pp/Surface.cc b/SDL2pp/Surface.cc
index a6b991c..f9fca5f 100644
--- a/SDL2pp/Surface.cc
+++ b/SDL2pp/Surface.cc
@@ -154,7 +154,7 @@ Surface& Surface::SetClipRect(const Optional<Rect>& rect) {
 	return *this;
 }
 
-Surface& Surface::SetColorKey(int flag, Uint32 key) {
+Surface& Surface::SetColorKey(bool flag, Uint32 key) {
 	if (SDL_SetColorKey(surface_, flag, key) != 0)
 		throw Exception("SDL_SetColorKey failed");
 	return *this;
diff --git a/SDL2pp/Surface.hh b/SDL2pp/Surface.hh
index 1b5c4f1..bebf407 100644
--- a/SDL2pp/Surface.hh
+++ b/SDL2pp/Surface.hh
@@ -430,7 +430,7 @@ public:
 	/// \see http://wiki.libsdl.org/SDL_SetColorKey
 	///
 	////////////////////////////////////////////////////////////
-	Surface& SetColorKey(int flag, Uint32 key);
+	Surface& SetColorKey(bool flag, Uint32 key);
 
 	////////////////////////////////////////////////////////////
 	/// \brief Set an additional alpha value used in blit operations