diff --git a/src/osgViewer/GNUmakefile b/src/osgViewer/GNUmakefile
index d91a458b7..99328486d 100644
--- a/src/osgViewer/GNUmakefile
+++ b/src/osgViewer/GNUmakefile
@@ -16,6 +16,7 @@ CXXFILES = \
 ifeq ($(OS),Darwin)
   ifeq ($(USE_AGL),yes)
      CXXFILES += GraphicsWindowCarbon.cpp
+     LIBS     += -framework AGL
   else 
     ifeq ($(USE_CGL),yes)
        CXXFILES += GraphicsWindowCarbon.cpp