diff --git a/qrexec/Makefile b/qrexec/Makefile
index be1add1..5a24850 100644
--- a/qrexec/Makefile
+++ b/qrexec/Makefile
@@ -1,5 +1,5 @@
 CC=gcc
-CFLAGS+=-I. -g -Wall -Wextra -Werror -pie -fPIC `pkg-config --cflags vchan-$(BACKEND_VMM)`
+CFLAGS+=-I. -g -O2 -Wall -Wextra -Werror -pie -fPIC `pkg-config --cflags vchan-$(BACKEND_VMM)`
 LIBS=`pkg-config --libs vchan-$(BACKEND_VMM)` -lqrexec-utils