diff --git a/samples/Makefile.am b/samples/Makefile.am
index 2c3ba25..4df3627 100644
--- a/samples/Makefile.am
+++ b/samples/Makefile.am
@@ -9,7 +9,7 @@ BIN_TESTS = \
 TESTS_ENVIRONMENT = CRITERION_ALWAYS_SUCCEED=1
 
 check_PROGRAMS := $(BIN_TESTS)
-CFLAGS = -I$(top_srcdir)/include/ -std=c99
+CFLAGS = -I$(top_srcdir)/include/ -std=c99 -Wall -Wextra
 LDADD = -L$(top_srcdir)/ -lcriterion
 
 SCRIPT_TESTS = tests/tap_test.sh \