diff --git a/libjp3dvm/CMakeLists.txt b/libjp3dvm/CMakeLists.txt
index f27ca1d4..23482483 100644
--- a/libjp3dvm/CMakeLists.txt
+++ b/libjp3dvm/CMakeLists.txt
@@ -1,5 +1,7 @@
 IF(UNIX OR CYGWIN)
  ADD_DEFINITIONS(-O3)
+ELSEIF(MINGW)
+ ADD_DEFINITIONS(-Os)
 ELSEIF(WIN32)
   ADD_DEFINITIONS(/Os)
 ENDIF(UNIX OR CYGWIN)