This page lists the World Best Year Performance in the year 1991 in the men's decathlon. One of the main events during this season were the 1991 IAAF World Championships in Tokyo, Japan, where the competition started on Thursday August 29, 1991, and ended on Friday August 30, 1991.
| Rank | Points | Athlete | Venue | Date | Note | |
|---|---|---|---|---|---|---|
| 1 | 8812 | Tokyo, Japan | 1991-08-30 | |||
| 2 | 8549 | Tokyo, Japan | 1991-08-30 | |||
| 3 | 8518 | Helmond, Netherlands | 1991-07-07 | |||
| 4 | 8467 | New York City, United States | 1991-06-13 | |||
| 5 | 8402 | Helmond, Netherlands | 1991-07-07 | |||
| 6 | 8379 | Tokyo, Japan | 1991-08-30 | |||
| 7 | 8318 | Tokyo, Japan | 1991-08-30 | PB | ||
| 8 | 8306 | Alhama de Murcia, Spain | 1991-06-02 | |||
| 9 | 8278 | Götzis, Austria | 1991-06-16 | |||
| 10 | 8267 | Tokyo, Japan | 1991-08-30 | |||
| 11 | 8233 | Tokyo, Japan | 1991-08-30 | |||
| 12 | 8224 | Emmitsburg, United States | 1991-09-29 | |||
| 13 | 8211 | Helmond, Netherlands | 1991-07-07 | |||
| 14 | 8166 | Baton Rouge, United States | 1991-03-30 | |||
| 15 | 8156 | Götzis, Austria | 1991-06-16 | |||
| 16 | 8141 | Budapest, Hungary | 1991-09-15 | |||
| 17 | 8119 | New York City, United States | 1991-06-13 | |||
| 18 | 8093 | Kielce, Poland | 1991-06-16 | |||
| 19 | 8079 | New York City, United States | 1991-06-13 | |||
| Sheffield, United Kingdom | 1991-07-24 | |||||
| 21 | 8076 | Helmond, Netherlands | 1991-07-07 | |||
| 22 | 8062 | Götzis, Austria | 1991-06-16 | |||
| 23 | 8030 | Baton Rouge, United States | 1991-03-30 | |||
| 24 | 8018 | Kyiv, Soviet Union | 1991-06-20 | |||
| 25 | 8017 | Talence, France | 1991-09-22 |