This is a list of missing biography articles for athletes who ranked in the top 25 of an individual event at the 1991 World Championships in Athletics. Compiled on 1 February 2020, 76 athletes were missing at creation. Athletes in bold finished in the top ten.
- 100 m
- 200 m
- 400 m
- 800 m
- Robert Kibet
- Markus Trinkler
- Esko Parpala
- Valeriy Starodubtsev
- Tuuli Merikoski
- 1500 m
- Mikael Svensson
- Mitsuhiro Okuyama
- Yvonne van der Kolk
- Darcy Arreola
- Irini Theodoridou
- Karin Medin
- 3000 m
- Anke Schaning
- Iulia Ionescu
- Jana Kučeríková
- 10,000 m
- Andy Bristow
- Katsumi Ikeda
- Geraldo de Assis
- Wang Yongmei
- 100 m hurdles
- Arnita Myricks
- Monica Pellegrinelli
- 400 m hurdles
- 3000 m s'chase
- Gábor Markó
- Benito Nogales
- Akira Nakamura (runner)
- José Carlos Pereira (runner)
- Marathon
- Tekeye Gebrselassie
- Sam Carey (athlete)
- Dave Buzza
- Vladimir Bukhanov
- Motsemme Kgaotsang
- Joy Smith (athlete)
- Yi-Lo Man
- Graciela Caizabanda
- 10 km walk
- Sun Yan (racewalker)
- Andrea Bruckmann
- Lynn Weik
- 50 km walk
- High jump
- Pole vault
- Sazan Fisheku
- Kelly Riley
- Long jump
- Triple jump
- Don Parish (triple jumper)
- Shot put
- Lim Chee-Wee
- Iammo Launa
- Mihaela Oana
- Seng Tea Ai
- Discus throw
- József Ficsór
- Marcel Tirle
- Marie-Paule Geldhof
- Hammer throw
- Javelin throw
- Decathlon
- Paul Scott (decathlete)
- Jan Trefny
- Saša Karan
- Heptathlon