diff --git a/makefile.unix b/makefile.unix
index e7729adca..10c4eece7 100644
--- a/makefile.unix
+++ b/makefile.unix
@@ -29,7 +29,7 @@ LIBS= \
 
 WXDEFS=-D__WXGTK__ -DNOPCH
 DEBUGFLAGS=-g -D__WXDEBUG__
-CFLAGS=-O2 -Wno-invalid-offsetof -Wformat $(DEBUGFLAGS) $(WXDEFS) $(INCLUDEPATHS)
+CFLAGS=-O0 -Wno-invalid-offsetof -Wformat $(DEBUGFLAGS) $(WXDEFS) $(INCLUDEPATHS)
 HEADERS=headers.h strlcpy.h serialize.h uint256.h util.h key.h bignum.h base58.h \
     script.h db.h net.h irc.h main.h rpc.h uibase.h ui.h init.h sha.h