This study describes the prevalence of self-medication and associated factors among nursing workers. This epidemiological sectional study included 1,509 working nurses from two public hospitals in Rio de Janeiro, Brazil. The medications were identified and classified according to the Anatomical Therapeutic Chemical Index. The self-medication prevalence was 24.2% and the most reported anatomical group treated was the nervous system, while the therapeutic group included analgesics. Self-medication was more prevalent among young people, individuals with minor psychiatric disturbances, non-hypertensive individuals, those who did not exercise, those who reported a disease or injury in the last 15 days, with the highest number of self-diagnosed diseases, nurses, professionals with temporary work contracts and those highly involved with their work. Self-medication is a frequent practice among the nursing team members and is associated with factors that should be taken into account when planning strategies aimed at improving workers' health conditions.