diff --git a/configure.ac b/configure.ac
index 065ac68..5af20de 100755
--- a/configure.ac
+++ b/configure.ac
@@ -88,7 +88,7 @@
 AC_PROG_INSTALL
 AC_PROG_LIBTOOL
 AC_PROG_MAKE_SET
-AC_PROG_BISON
+AC_PROG_BISON(2.5)
 AC_PROG_YACC
 AC_PROG_LEX
 AM_PROG_LEX