The 1998 Australian Sports Sedan Championship was a CAMS sanctioned motor racing title for drivers of Group 2D Sports Sedans. It was the 14th Australian Sports Sedan Championship to be awarded by CAMS.
The championship was contested over a five round series.
Rounds were contested over three races.
Championship points were awarded on a 10-9-8-7-6-5-4-3-2-1 basis for the first ten positions attained in qualifying at each round . No points were awarded for Race 1, however the results were used to determine the starting grid for Race 2. Championship points were awarded on a 21-19-17-16-15-14-13-12-11-10 basis for the first ten positions in both Race 2 and Race 3 of each round.