diff --git a/examples/osgviewerCocoa/CMakeLists.txt b/examples/osgviewerCocoa/CMakeLists.txt
index 25488220f..cb11af1ef 100644
--- a/examples/osgviewerCocoa/CMakeLists.txt
+++ b/examples/osgviewerCocoa/CMakeLists.txt
@@ -1,6 +1,6 @@
 FILE(GLOB ui_files_1 "English.lproj/*.strings")
 FILE(GLOB ui_files_2 "English.lproj/MainMenu.nib/*.nib")
-SET(TARGET_SRC ViewerCocoa.mm main.m Info.plist ${ui_files_1} ${ui_files_2})
+SET(TARGET_SRC ViewerCocoa.mm main.mm Info.plist ${ui_files_1} ${ui_files_2})
 
 SET(TARGET_EXTERNAL_LIBRARIES osg ${COCOA_LIBRARY})
 SET_SOURCE_FILES_PROPERTIES(Info.plist PROPERTIES MACOSX_PACKAGE_LOCATION .)
diff --git a/examples/osgviewerCocoa/main.m b/examples/osgviewerCocoa/main.mm
similarity index 99%
rename from examples/osgviewerCocoa/main.m
rename to examples/osgviewerCocoa/main.mm
index efd4cf593..41dd4333e 100644
--- a/examples/osgviewerCocoa/main.m
+++ b/examples/osgviewerCocoa/main.mm
@@ -17,7 +17,7 @@
 */
 
 //
-//  main.m
+//  main.mm
 //  osgsimpleviewerCocoa
 //
 //  Created by Eric Wing on 11/13/06.