Well, I know what is supposed to happen so I got my point. But anyone still using SQLServer 2000 should be warned about this - the behaviour is erratic, it may decide that although the proc name begins sp_ it's not going to look for it in master. So it's best always to use exec master..sp_ (in modern SQLServer, exec sys.sp_ - this is explicitly recommended in BOL for 2008) rather than just sp_.