diff --git a/gdk/Makefile.in b/gdk/Makefile.in
index 109339687..85ff0d5a7 100755
--- a/gdk/Makefile.in
+++ b/gdk/Makefile.in
@@ -9,7 +9,7 @@ windows:
 linux: gdk-sharp.dll
 
 gdk-sharp.dll: *.cs generated/*.cs
-	$(MCS) --unsafe --target library -L ../glib -L ../pango -L ../atk -r glib-sharp.dll -r pango-sharp.dll -r atk-sharp.dll -o gdk-sharp.dll --recurse '*.cs'
+	$(MCS) --unsafe --target library -r System.Drawing -L ../glib -L ../pango -L ../atk -r glib-sharp.dll -r pango-sharp.dll -r atk-sharp.dll -o gdk-sharp.dll --recurse '*.cs'
 
 clean:
 	rm -f *.dll
diff --git a/gdk/makefile.win32 b/gdk/makefile.win32
index 2f6e6c253..4d901d422 100644
--- a/gdk/makefile.win32
+++ b/gdk/makefile.win32
@@ -3,7 +3,7 @@ all: windows
 windows:
 	cat *.cs generated/*.cs > allthesource.cs
 	../mapdllnames.pl allthesource.cs
-	$(CSC) /unsafe /target:library /r:../glib/glib-sharp.dll /r:../pango/pango-sharp.dll /r:../atk/atk-sharp.dll /out:gdk-sharp.dll allthesource.cs
+	$(CSC) /unsafe /target:library /r:System.Drawing.dll /r:../glib/glib-sharp.dll /r:../pango/pango-sharp.dll /r:../atk/atk-sharp.dll /out:gdk-sharp.dll allthesource.cs
 	rm allthesource.cs
 
 docs: