diff --git a/src/SConstruct b/src/SConstruct
index 5f1ce6a..96a197d 100644
--- a/src/SConstruct
+++ b/src/SConstruct
@@ -29,7 +29,7 @@ flags = ' -lm -Wall -fmessage-length=0 ' + ldflags
 if int(DEBUG):
 	flags += ' -O0 -g -fdebug-prefix-map=src=../src'
 else:
-	flags += ' -O3 '
+	flags += ' -O3 -DNDEBUG '
 
 if int(WITH_FULL_UNICODE_FONT):
 	flags += ' -DWITH_FULL_UNICODE_FONT'