The 1990 Cincinnati Open, (also known as the Thriftway ATP Championships for sponsorship reasons) was a tennis tournament played on outdoor hard courts. It was the 91st edition of the tournament and was part of the ATP Super 9 of the 1990 ATP Tour. It took place in Cincinnati, Ohio, United States from August 13 through August 20, 1990.
The tournament had previously appeared on the Tier III Series of the WTA Tour but no event was held from 1989 to 2003.
The singles field was headlined by World No. 1, Wimbledon champion, Tokyo outdoor, Los Angeles, Indian Wells Masters title holder and Australian Open runner-up, 1987 Cincinnati winner Stefan Edberg, San Francisco, Washington, Key Biscayne winner, French Open finalist Andre Agassi and Barcelona, Madrid winner, French Open losing finalist Andrés Gómez. Other top seeds were Rotterdam, Orlando titlist Brad Gilbert, Tokyo outdoor finalist Aaron Krickstein, Jay Berger, Michael Chang and John McEnroe.
Stefan Edberg defeated Brad Gilbert 6–1, 6–1 
- It was Stefan Edberg's 5th title of the year and his 26th overall. It was his 2nd Masters title of the year and overall.
Darren Cahill / Mark Kratzmann defeated Neil Broad / Gary Muller 7–6, 6–2.