The 1998 Arizona Diamondbacks season was the Diamondbacks' inaugural season. They looked to contend in what was a strong National League Western Division. They finished the season 33 games behind the National League Champion San Diego Padres with a record of 65-97, last in the division. However, they would improve in 1999, finishing with a record of 100-62 and winning 35 games more than the previous year.