diff --git a/Surface_mesher/demo/Surface_mesher/makefile b/Surface_mesher/demo/Surface_mesher/makefile
index 1152355f389..c23390c40a1 100644
--- a/Surface_mesher/demo/Surface_mesher/makefile
+++ b/Surface_mesher/demo/Surface_mesher/makefile
@@ -19,6 +19,7 @@ default-rule: all
 CXXFLAGS = \
            -I../../include \
 	   -I../../../Mesh_2/include \
+	   -I../../../Mesh_3/include \
            -I../../../Data_structure_for_queries_3/include \
            $(CGAL_CXXFLAGS) \
            $(LONG_NAME_PROBLEM_CXXFLAGS) \