diff --git a/ChangeLog b/ChangeLog
index ece9230a9a..9c68d832ef 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Sat Apr 30 18:11:44 2016  Tanaka Akira  <akr@fsij.org>
+
+	* bignum.c (Init_Bignum): Define Integer#GMP_VERSION.
+
 Sat Apr 30 16:58:18 2016  Tanaka Akira  <akr@fsij.org>
 
 	* numeric.c (int_remainder): Define Integer#remainder.
diff --git a/bignum.c b/bignum.c
index c23f439087..048568d035 100644
--- a/bignum.c
+++ b/bignum.c
@@ -6890,6 +6890,7 @@ Init_Bignum(void)
 #ifdef USE_GMP
     /* The version of loaded GMP. */
     rb_define_const(rb_cBignum, "GMP_VERSION", rb_sprintf("GMP %s", gmp_version));
+    rb_define_const(rb_cInteger, "GMP_VERSION", rb_sprintf("GMP %s", gmp_version));
 #endif
 
     power_cache_init();