diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2aecdbb72..d42b0191b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -20,7 +20,7 @@ set(CPACK_COMPONENTS_ALL assimp-bin ${LIBASSIMP_COMPONENT} assimp-dev)
 if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX)
   add_definitions(-fPIC) # this is a very important switch and some libraries seem now to have it....
   ## hide all not-exported symbols
-  add_definitions( -fvisibility=hidden )
+  add_definitions( -fvisibility=hidden -Wall )
 endif()
 
 INCLUDE (FindPkgConfig)