diff --git a/dump.h b/dump.h
index 04cadda..90bef76 100644
--- a/dump.h
+++ b/dump.h
@@ -6,7 +6,7 @@
 #include <string.h>
 
 /* Some things I use for debugging */
-#ifdef DEBUG
+#ifndef DEBUG
 #  define DUMPf(fmt, args...)
 #else
 #  define DUMPf(fmt, args...) fprintf(stderr, "%s:%d " fmt "\n", __FILE__,  __LINE__, ##args)