The 1990 All Japan Sports Prototype Car Endurance Championship was the eighth season of the All Japan Sports Prototype Championship. The 1990 champion was the #24 Nissan Motorsports Nissan R91CP driven by Masahiro Hasemi and Anders Olofsson.
All races were held in Japan.
| Round | Race | Circuit | Date |
|---|---|---|---|
| 1 | JAF Grand Prix All Japan Fuji 500 km | Fuji Speedway | 11 March |
| 2 | Interchallenge Fuji 1000 km | Fuji Speedway | 5 May |
| 3 | All Japan Fuji 500 Miles | Fuji Speedway | 22 July |
| 4 | International Suzuka 1000 km | Suzuka Circuit | 26 August |
| 5 | SUGO International 500 km | Sportsland SUGO | 16 September |
| 6 | All Japan Fuji 1000 km | Fuji Speedway | 7 October |
Overall winner in bold. Season results as follows: [1]
| Round | Circuit | Winning team |
|---|---|---|
| Winning drivers | ||
| 1 | Mt. Fuji | #36 Toyota Team TOM'S Toyota 90C-V |
| | ||
| 2 | Mt. Fuji | Race Cancelled |
| 3 | Mt. Fuji | #24 Nissan Motorsports Nissan R90CP |
| | ||
| 4 | Suzuka Circuit Report | #23 Nissan Motorsports Nissan R90CP |
| | ||
| 5 | Sportsland SUGO | #24 Nissan Motorsports Nissan R90CP |
| | ||
| 6 | Mt. Fuji Report | #38 Toyota Team SARD Toyota 89C-V |
| | ||
| Rank | Drivers | Number/Team | Points | Wins | Distance |
|---|---|---|---|---|---|
| 1 | | #24 Nissan Motorsports Nissan R90CP | 67 | 2 | 2171.329 km |
| 2 | | 67 | 2 | 1570.479 km | |
| 3 | | #23 Nissan Motorsports Nissan R90CP | 67 | 1 | 2094.272 km |
| 4 | | 67 | 1 | 1696.405 km | |
| 5 | | #100 Trust Racing Porsche 962C | 47 | 0 | 1669.178 km |
| 6 | | 47 | 0 | 1112.97 km | |
| 7 | | #2 Alpha Nova Racing Porsche 962C | 43 | 0 | 1859.862 km |
| 8 | | 43 | 0 | 1105.556 km |
| Rank | Make | Points | Wins |
|---|---|---|---|
| 1 | Nissan | 90 | 3 |
| 2 | Porsche | 69 | 0 |
| 3 | Toyota | 64 | 2 |
| 4 | Mazda | 12 | 0 |
| 5 | Spice | 1 | 0 |