diff --git a/CMakeLists.txt b/CMakeLists.txt
index e261443b0..8b8b43c86 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -195,10 +195,12 @@ IF(UNIX)
     SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -m32 -march=i686")
     SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -m32 -march=i686")
   ENDIF()
+  STRING(REPLACE "-DNDEBUG" "" CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
 ELSEIF(MSVC)
   # for msvc, tell it to always use 8-byte pointers to member functions to avoid confusion
   SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /vmg /vmm /MP")
   SET(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} /Od")
+  STRING(REPLACE "/DNDEBUG" "" CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
 ENDIF()
 
 # use shared libraries for protobuf