diff --git a/CMakeLists.txt b/CMakeLists.txt
index 43a170745..dec306881 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -174,6 +174,7 @@ else()
   endif()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
   if(NOT CMAKE_BUILD_TYPE STREQUAL "Debug")
+    add_definitions(-DNDEBUG)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2 -fno-omit-frame-pointer")
     include(CheckCXXCompilerFlag)
     CHECK_CXX_COMPILER_FLAG("-momit-leaf-frame-pointer" HAVE_OMIT_LEAF_FRAME_POINTER)