diff --git a/mex/build/matlab/configure.ac b/mex/build/matlab/configure.ac
index f706e1192bd4d8d4de723feb459c015236815bf8..f1e77acaa1c3924aeea6485f1cc6e38749b76a78 100644
--- a/mex/build/matlab/configure.ac
+++ b/mex/build/matlab/configure.ac
@@ -50,6 +50,9 @@ case ${host_os} in
     ;;
 esac
 
+CFLAGS="$CFLAGS -Wall"
+CXXFLAGS="$CXXFLAGS -Wall"
+
 AC_PROG_CC
 AC_PROG_CXX
 AC_PROG_RANLIB
diff --git a/mex/build/octave/configure.ac b/mex/build/octave/configure.ac
index 14cf98798eda63e6553764c3e4040bcbfa927052..580ab6965622e4a08b65de01bfe8cb08960a1773 100644
--- a/mex/build/octave/configure.ac
+++ b/mex/build/octave/configure.ac
@@ -31,6 +31,9 @@ if test "x$MKOCTFILE" != "x"; then
   CXXFLAGS=`$MKOCTFILE -p CXXFLAGS`
 fi
 
+CFLAGS="$CFLAGS -Wall"
+CXXFLAGS="$CXXFLAGS -Wall"
+
 AC_PROG_CC
 AC_PROG_CXX
 AC_PROG_RANLIB