diff --git a/include/mruby/internal.h b/include/mruby/internal.h
index 779f258df..8b04166e4 100644
--- a/include/mruby/internal.h
+++ b/include/mruby/internal.h
@@ -188,6 +188,7 @@ mrb_int mrb_bint_cmp(mrb_state *mrb, mrb_value x, mrb_value y);
 void mrb_gc_free_bint(mrb_state *mrb, struct RBasic *x);
 void mrb_bint_copy(mrb_state *mrb, mrb_value x, mrb_value y);
 size_t mrb_bint_memsize(mrb_value x);
+mrb_value mrb_bint_hash(mrb_state *mrb, mrb_value x);
 #endif
 
 #endif  /* MRUBY_INTERNAL_H */
diff --git a/mrbgems/mruby-bigint/core/bigint.c b/mrbgems/mruby-bigint/core/bigint.c
index 750940c7c..d5ff04aa5 100644
--- a/mrbgems/mruby-bigint/core/bigint.c
+++ b/mrbgems/mruby-bigint/core/bigint.c
@@ -1538,3 +1538,12 @@ mrb_bint_memsize(mrb_value x)
   struct RBigint *b = RBIGINT(x);
   return b->mp.sz * sizeof(mp_limb);
 }
+
+mrb_value
+mrb_bint_hash(mrb_state *mrb, mrb_value x)
+{
+  struct RBigint *b = RBIGINT(x);
+  uint32_t hash = mrb_byte_hash((uint8_t*)b->mp.p, b->mp.sz);
+  hash = mrb_byte_hash_step((uint8_t*)&b->mp.sn, sizeof(b->mp.sn), hash);
+  return mrb_int_value(mrb, hash);
+}
diff --git a/src/kernel.c b/src/kernel.c
index 54c08bdac..45a6b69d4 100644
--- a/src/kernel.c
+++ b/src/kernel.c
@@ -249,6 +249,11 @@ mrb_obj_frozen(mrb_state *mrb, mrb_value self)
 static mrb_value
 mrb_obj_hash(mrb_state *mrb, mrb_value self)
 {
+#ifdef MRB_USE_BIGINT
+  if (mrb_bigint_p(self)) {
+    return mrb_bint_hash(mrb, self);
+  }
+#endif
   return mrb_int_value(mrb, mrb_obj_id(self));
 }