diff --git a/src/common/simclist.c b/src/common/simclist.c
index 33f21e6d..a5da703f 100644
--- a/src/common/simclist.c
+++ b/src/common/simclist.c
@@ -71,8 +71,10 @@
 
 /* disable asserts */
 #ifndef SIMCLIST_DEBUG
+#ifndef NDEBUG
 #define NDEBUG
 #endif
+#endif
 
 #include <assert.h>