The 1989 Cincinnati Open was a tennis tournament played on outdoor hard courts at the Lindner Family Tennis Center in Cincinnati, 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.
Brad Gilbert defeated Stefan Edberg 6–4, 2–6, 7–6
- It was Gilbert's 4th title of the year and the 18th of his career.
Ken Flach / Robert Seguso defeated Pieter Aldrich / Danie Visser 6–4, 6–4
- It was Flach's 2nd title of the year and the 26th of his career. It was Seguso's 2nd title of the year and the 26th of his career.