diff --git a/configure.in b/configure.in
index 1525dc71..5711d674 100644
--- a/configure.in
+++ b/configure.in
@@ -1,6 +1,6 @@
 dnl Process this file with autoconf to produce a configure script.
 AC_INIT(reduce.c)
-AM_INIT_AUTOMAKE(bison,1.26)
+AM_INIT_AUTOMAKE(bison,1.27)
 AM_CONFIG_HEADER(config.h:config.hin)
 AC_PREREQ(2.13)