Since 1899, just 25 years after the first recorded playing of the sport in the United States, tennis tournaments have been staged in Cincinnati, and what is now known as the Western & Southern Open is the country's oldest professional tennis event still played in its original city.

An ATP tournament for most of its history, Cincinnati welcomed a WTA stop in 2004, and then in 2011 it became a joint event, with the men's and women's tournaments going on at the same time. Part of the Emirates Airline US Open Series, the event is held about 20 miles north of Cincinnati in Mason, Ohio, at the Lindner Family Tennis Center. It is the only tennis site in the nation outside of the USTA Billie Jean King National Tennis Center to have four permanent stadiums - each of which has lights for night play.

Since 2002, Western & Southern Financial Group has been title sponsor of the tournament, benefitting Cincinnati Children's Hospital Medical Center, Barrett Cancer Center and Tennis For City Youth. Champions include Kim Clijsters, Lindsay Davenport, Jelena Jankovic, Li Na and Maria Sharapova.