query of two tables returns too many rows, many more than the two tables contain

I have two tables I want to get out the rows that are different between them. The results I am getting is almost 50,000 rows, but the two tables, combined, contain only about 600 rows total. Here is the select statement - SELECT dealers.account_no, dealers.DealerName, blackgate_users.User_Name, blackgate_users.DealerName FROM dealers, blackgate_users WHERE dealers.account_no NOT LIKE blackgate_users.User_Name in these tables the dealers.account_no is the same data as the blackgate_users.User_Name dealers.DealerName is the same data as the blackgate_users.DealerName I just want the rows that are in the dealers table but not in the blackgate_users table. Thanks for any help, Chip Wiegand Computer Services Simrad, Inc 425-778-8821 425-771-7211 (FAX)