Objective: To investigate use and awareness of lawful and unlawful substances by amateur footballers in Yaounde, Cameroon. Methods: A total of 1116 amateur footballers (1037 male and 79 female) out of 1500 contacted participated in this study. They were divided into three groups: elite players (n = 314); local players (n = 723); female players (n = 79). They answered a questionnaire of 30 items grouped under six main topics: identification of players; use of lawful substances subject to certain restrictions on the International Olympic Committee (IOC) list; use of IOC banned substances; doping behaviour; awareness of doping; food supplements. The results of the questionnaire were scrutinised using Microstat software, and the level of significance was p<0.05. Results: (a) Use by our footballers of a banned substance (cocaine) and substances subject to certain restrictions (alcoholic drinks, methylated spirits, and banga (marijuana)). (b) Doping behaviour: use by our footballers of substances with similar effects to some IOC banned substances but not listed as such: tobacco, liboga, wie-wie (narcotic), bilibili (locally made alcohol drink). (c) A large intake of vitamin C (food supplements) in all three groups. In contrast, the footballers' knowledge of doping was vague. Conclusion: Preventive actions and an epidemiological study of doping among footballers are urgently required.