| Details | |
|---|---|
| Duration | March 5 – November 4 |
| Edition | 1st |
| Tournaments | 9 |
| Achievements (singles) | |
| Most tournament titles |  Stefan Edberg (3) |
| Most tournament finals | Stefan Edberg (5) |
1991 → | |
The 1990 ATP Championship Series, Single Week was a series of tennis tournament that was part of the 1990 ATP Tour, the elite tour for professional men's tennis organised by the Association of Tennis Professionals. It formed the tier below the Grand Slam tournaments.