| 1998 Great American Insurance ATP Championships | |
|---|---|
| Date | August 10–17 |
| Edition | 97th |
| Category | ATP Super 9 |
| Draw | 56S / 28D |
| Prize money | $2,200,000 |
| Surface | Hard / outdoor |
| Location | Mason, United States |
| Venue | Lindner Family Tennis Center |
| Champions | |
| Singles | |
 Patrick Rafter[1][2] | |
| Doubles | |
 Mark Knowles / Daniel Nestor[1][3] | |
The1998 Cincinnati Open, known by the corporate title of theGreat American Insurance ATP Championships was a tennis tournament played onoutdoor hard courts. It was the 95th edition of thetournament previously known as theThriftway ATP Championships, and was part of theATP Super 9 of the1998 ATP Tour. It took place inMason, United States, from August 10 through August 17, 1998.
The tournament had previously appeared on theTier III of theWTA Tour but no event was held from 1989 to 2003.
Patrick Rafter defeated
Pete Sampras, 1–6, 7–6(7–2), 6–4
Mark Knowles /Daniel Nestor defeated
Olivier Delaître /Fabrice Santoro, 6–1, 2–1, ret.