diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8f8087d4505f633303bbcefa1865f327accb1d64..c81e49612946a850fd6ebf7c5f1dbff20ac416ed 100755
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,6 +12,7 @@ if( ScalFMM_USE_MPI )
 	include(CMakeForceCompiler)
 	CMAKE_FORCE_C_COMPILER(mpicc "MPI C Compiler") 
     	CMAKE_FORCE_CXX_COMPILER(mpicxx "MPI C++ Compiler")
+	set(ScalFMM_USE_MPI ON CACHE BOOL "ScalFmm use MPI")
 else()
 	MESSAGE(STATUS "Remove CMake cache and run cmake .. -DScalFMM_USE_MPI=ON to enable MPI" )
 endif(ScalFMM_USE_MPI)