diff --git a/Makefile b/Makefile
index 00b95f8c..855f81f7 100644
--- a/Makefile
+++ b/Makefile
@@ -21,7 +21,7 @@ include config.mk
 endif
 
 ifeq ($(PROFILE),1)
-CXXFLAGS+=-fprofile-arcs -ftest-coverage
+CXXFLAGS+=-O0 -fprofile-arcs -ftest-coverage
 endif
 
 LIB_SOURCES:=$(shell cat mk/libbeuter.deps)