The Unono Wa Maore survey provided baseline data on psychoactive substance use in Mayotte in 2019, based on a random sample of 4,770 people aged 15 to 69. For most indicators, levels of psychoactive substance use (alcohol, tobacco, cannabis) were significantly lower than those observed in mainland France. However, as in mainland France, men were more likely to use these substances than women. The proportion of people who had ever tried alcohol was 26% among those aged 18–69 and 8% among those aged 15–17. The proportion of those aged 18–69 who had consumed alcohol in the past year was 14%. The prevalence of daily smoking was 11% among adults (21% among men and 2% among women) and 4% among minors. The proportion of people who had tried cannabis was 6% among those aged 18–69 and 3% among those aged 15–17.