Key points: The objective of this study was to estimate the prevalence of asthma among all artisans and merchants enrolled in the Social Security system for the self-employed (formerly the Social Security Scheme for the Self-Employed, RSI) using an asthma identification algorithm based on anti-asthmatic medications submitted for reimbursement; by sector of activity. The analysis revealed a high risk of asthma: in sectors known to be at risk, such as the food industry or hairdressing; and in sectors not previously identified as high-risk in the literature, such as passenger taxi services, driving schools, ambulance services, retail businesses at markets, and fairground rides and amusement parks. Prevention measures: in sectors known to be at risk for asthma, these measures must be continued; in high-risk sectors not previously identified, it is necessary to better characterize the existing exposures in order to better define prevention measures in collaboration with the Social Security system for the self-employed. It would be valuable to track changes over time in sectors at risk for asthma through repeated cross-sectional analyses using medical-administrative databases.