The 1989 Thriftway ATP Championship, also known as the Cincinnati Open, was a men's tennis tournament played on outdoor hard courts at the Lindner Family Tennis Center in Mason, Ohio in the United States that was part of the 1989 Nabisco Grand Prix.

The tournament was held from August 14 through August 20, 1989.

Fifth-seeded Brad Gilbert won the singles title.

Brad Gilbert defeated Stefan Edberg 6–4, 2–6, 7–6 Ken Flach / Robert Seguso defeated Pieter Aldrich / Danie Visser 6–4, 6–4