diff --git a/gtk/Makefile.in b/gtk/Makefile.in
index 8600fc524..eb2fa4571 100755
--- a/gtk/Makefile.in
+++ b/gtk/Makefile.in
@@ -8,7 +8,7 @@ windows:
 linux: gtk-sharp.dll
 
 gtk-sharp.dll: *.cs generated/*.cs
-	$(MCS) --unsafe --target library -L ../glib -L ../pango -L ../atk -L ../gdk -r glib-sharp -r pango-sharp -r atk-sharp -r gdk-sharp -o gtk-sharp.dll --recurse '*.cs'
+	$(MCS) --unsafe --target library -r System.Drawing -L ../glib -L ../pango -L ../atk -L ../gdk -r glib-sharp -r pango-sharp -r atk-sharp -r gdk-sharp -o gtk-sharp.dll --recurse '*.cs'
 
 clean:
 	rm -f *.dll