1991 All Japan Sports Prototype Car Endurance Championship

The 1991 All Japan Sports Prototype Car Endurance Championship was the ninth season of the All Japan Sports Prototype Championship. The 1991 champion was the #23 Nissan Motorsports Nissan R91CP driven by Kazuyoshi Hoshino and Toshio Suzuki.

Schedule
All races were held in Japan.

Season results
Season results as follows: