diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4484e373..87b5ed41 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -81,9 +81,9 @@ if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
   set (WARN_FLAGS "${WARN_FLAGS} -Wno-covered-switch-default")
   set (WARN_FLAGS "${WARN_FLAGS} -Wno-missing-noreturn -Wno-unknown-pragmas")
   set (WARN_FLAGS "${WARN_FLAGS} -Wno-gnu-zero-variadic-macro-arguments")
-  set (WARN_FLAGS "${WARN_FLAGS} -Wconversion -Werror")
+  set (WARN_FLAGS "${WARN_FLAGS} -Wconversion")
 elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-  set (WARN_FLAGS "-Wall -Wno-unknown-pragmas -Wconversion -Werror")
+  set (WARN_FLAGS "-Wall -Wno-unknown-pragmas -Wconversion")
   if (CMAKE_CXX_COMPILER_VERSION STREQUAL "" OR
       CMAKE_CXX_COMPILER_VERSION VERSION_LESS "4.7")
     set (CXX11_FLAGS "-std=c++0x")