1 files changed, 1 insertions, 1 deletions
diff --git a/struct.c b/struct.c
index f1f361f953..b36dd37e4b 100644
--- a/struct.c
+++ b/struct.c
@@ -794,7 +794,7 @@ rb_struct_to_a(VALUE s)
 static VALUE
 rb_struct_to_h(VALUE s)
 {
-    VALUE h = rb_hash_new();
+    VALUE h = rb_hash_new_with_size(RSTRUCT_LEN(s));
     VALUE members = rb_struct_members(s);
     long i;