diff --git a/CMakeLists.txt b/CMakeLists.txt
index 99243a7d..9fcba388 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -52,7 +52,7 @@ enable_testing()
 
 
 if(APPLE)
-  set(CMAKE_OSX_DEPLOYMENT_TARGET 10.10.5)          
+  set(CMAKE_OSX_DEPLOYMENT_TARGET 10.10.5 CACHE STRING "Minimum OS X deployment version")          
 endif()
 
 set(USE_PCH FALSE CACHE BOOL "Use shared precompiled headers")