Before the 1998 season, the Major Indoor Lacrosse League was renamed to be the National Lacrosse League, in the process increasing the length of the regular season from ten to twelve games. The first season as the NLL and the 12th season overall, began on January 3, 1998, and concluded with the second championship game on April 28. The championship was decided by a best-two-of-three series, with the Philadelphia Wings defeating the Baltimore Thunder 16–12 in the first game and 17–12 in the second.
x: Clinched playoff berth; c: Clinched playoff berth by crossing over to another division; y: Clinched division; z: Clinched best regular season record; GP: Games Played W: Wins; L: Losses; GB: Games back; PCT: Win percentage; Home: Record at Home; Road: Record on the Road; GF: Goals scored; GA: Goals allowed Differential: Difference between goals scored and allowed; GF/GP: Average number of goals scored per game; GA/GP: Average number of goals allowed per game
All Star Game
No All-Star Game was played in 1998.
Playoffs
Semifinals
Championship (best-of-3)
4
Buffalo
12
1
Philadelphia
17
2
Baltimore
0
1
Philadelphia
2
3
Rochester
14
2
Baltimore
15
Game 1: Baltimore 12 @ Philadelphia 16 Game 2: Philadelphia 17 @ Baltimore 12
Awards are also given out monthly for the best overall player and best rookie. The 1998 season was the first season that the Rookie of the Month award was given out.