diff --git a/libgrive/CMakeLists.txt b/libgrive/CMakeLists.txt
index 54776bd..3b48e3c 100644
--- a/libgrive/CMakeLists.txt
+++ b/libgrive/CMakeLists.txt
@@ -142,6 +142,10 @@ target_link_libraries( btest
 	${Boost_LIBRARIES}
 )
 
+if ( ${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD" )
+  set( CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-c++11-narrowing" )
+endif ( ${CMAKE_SYSTEM_NAME} MATCHES "FreeBSD" )
+
 if ( WIN32 )
 else ( WIN32 )
 	set_target_properties( btest