diff --git a/object.c b/object.c
index 1e005e5..279fec8 100644
--- a/object.c
+++ b/object.c
@@ -1622,7 +1622,7 @@ rb_mod_initialize(VALUE module)
 static VALUE
 rb_class_initialize(int argc, VALUE *argv, VALUE klass)
 {
-    VALUE super;
+    VALUE super, i;
 
     if (RCLASS_SUPER(klass) != 0 || klass == rb_cBasicObject) {
 	rb_raise(rb_eTypeError, "already initialized class");
@@ -1634,6 +1634,11 @@ rb_class_initialize(int argc, VALUE *argv, VALUE klass)
 	rb_scan_args(argc, argv, "01", &super);
 	rb_check_inheritable(super);
     }
+    for(i = super; i && i != rb_cBasicObject; i = RCLASS_SUPER(i)) {
+	if(i == klass) {
+	    rb_raise(rb_eTypeError, "circular inheritance detected");
+	}
+    }
     RCLASS_SUPER(klass) = super;
     rb_make_metaclass(klass, RBASIC(super)->klass);
     rb_class_inherited(super, klass);