The 1991 Suzuka 1000 km was the fourth round of the 1991 All Japan Sports Prototype Car Endurance Championship season and the 20th running of the 1000 km Suzuka. It took place at Suzuka Circuit, Japan on August 25, 1991.
Results are as follows:[1]
| Pos | Class | No | Team | Drivers | Chassis | Tyre | Laps |
|---|---|---|---|---|---|---|---|
| 1 | C1 | 38 |  Roland Ratzenberger Pierre-Henri Raphanel Naoki Nagasaka | Toyota 91C-V | 171 | ||
| 2 | C1 | 27 | From A Racing | Nissan R91CK | 171 | ||
| 3 | C1 | 1 | Nissan Motorsport | Masahiro Hasemi Anders Olofsson | Nissan R91CP | 167 | |
| 4 | C1 | 36 | TOM'S | Hitoshi Ogawa Masanori Sekiya Andy Wallace | 166 | ||
| 5 | C1 | 100 | Trust Racing | George Fouche Steven Andskar | 166 | ||
| 6 | GTP | 201 | Mazdaspeed | Takashi Yorino Yojiro Terada David Kennedy | Mazda 787B | 165 | |
| 7 | GTP | 230 | Pleasure Racing | Tetsuji Shiratori Masatomo Shimizu Shuji Fujii | Mazda 767 | 147 | |
| DNF | C1 | 23 | Nissan Motorsport | Kazuyoshi Hoshino Toshio Suzuki | Nissan R91CP | 162 | |
| DNF | C1 | 25 | Team LeMans | Hideki Okada Maurizio Sandro Sala Takao Wada | Nissan R90CP | 68 | |
| DNF | C1 | 91 | Team 0123 | Julian Bailey Kenny Acheson | 54 | ||
| DNF | C1 | 18 | TWR Suntech | John Nielsen Mauro Martini Jeff Krosnoff | Jaguar XJR-11 | 46 | |
| DNF | C1 | 37 | Toyota Team TOM'S | Geoff Lees Eje Elgh Andy Wallace | 34 | ||