| 1998 NPB season | |
|---|---|
| League | Nippon Professional Baseball | 
| Sport | Baseball | 
| Regular season | |
| Season MVP | CL: Kazuhiro Sasaki (YOK) PL: Kazuo Matsui (SEI) | 
| League postseason | |
| CL champions | Yokohama BayStars | 
| CL runners-up | Chunichi Dragons | 
| PL champions | Seibu Lions | 
| PL runners-up | Nippon-Ham Fighters | 
| Japan Series | |
| Champions | Yokohama BayStars | 
| Runners-up | Seibu Lions | 
| Finals MVP | Takanori Suzuki (YOK) | 
The 1998 Nippon Professional Baseball season was the 49th season of operation for the league.
| Central League [1] | G | W | L | T | Pct. | GB | 
|---|---|---|---|---|---|---|
| Yokohama BayStars | 136 | 79 | 56 | 1 | .585 | -- | 
| Chunichi Dragons | 136 | 75 | 60 | 1 | .556 | 4.0 | 
| Yomiuri Giants | 135 | 73 | 62 | 0 | .541 | 6.0 | 
| Yakult Swallows | 135 | 66 | 69 | 0 | .489 | 13.0 | 
| Hiroshima Toyo Carp | 135 | 60 | 75 | 0 | .444 | 19.0 | 
| Hanshin Tigers | 135 | 52 | 83 | 0 | .385 | 27.0 | 
| Pacific League [2] | G | W | L | T | Pct. | GB | 
|---|---|---|---|---|---|---|
| Seibu Lions | 135 | 70 | 61 | 4 | .534 | -- | 
| Nippon-Ham Fighters | 135 | 67 | 65 | 3 | .508 | 3.5 | 
| Orix BlueWave | 135 | 66 | 66 | 3 | .500 | 4.5 | 
| Fukuoka Daiei Hawks | 135 | 67 | 67 | 1 | .500 | 4.5 | 
| Kintetsu Buffaloes | 135 | 66 | 67 | 2 | .496 | 5.0 | 
| Chiba Lotte Marines | 135 | 61 | 71 | 3 | .462 | 9.5 | 
| Game | Score | Date | Location | Attendance | 
|---|---|---|---|---|
| 1 | BayStars – 9, Lions – 4 | October 18 | Yokohama Stadium | 29,025 [3] | 
| 2 | BayStars – 4, Lions – 0 | October 19 | Yokohama Stadium | 29,076 [3] | 
| 3 | Lions – 7, BayStars – 2 | October 22 | Seibu Dome | 31,599 [3] | 
| 4 | Lions – 4, BayStars – 2 | October 23 | Seibu Dome | 31,685 [3] | 
| 5 | Lions – 5, BayStars – 17 | October 24 | Seibu Dome | 31,756 [3] | 
| 6 | BayStars – 2, Lions – 1 | October 26 | Yokohama Stadium | 29,289 [3] |