This cross-sectional study focused on motorcycle couriers (work profile, work conditions, and traffic accidents) in Londrina and Maringá, Paraná State, Brazil. Data were collected from self-completed questionnaires in 2005-2006. In Londrina and Maringá, respectively, 377 and 500 motorcycle couriers completed the questionnaire, with mean ages of 28 and 29 years. Londrina showed a higher proportion of couriers that earned per delivery, worked both day and night or on night shifts only, and who worked more than 10 hours a day (p < 0.05). Despite greater exposure to hazardous work and traffic conditions in Londrina, there was no significant difference in the accident rates during the 12 months prior to the survey in Londrina and Maringá (2.89 and 2.80 per 100 person-months, respectively). The study detected precarious work conditions, high exposure to hazardous traffic conditions, and high accident rates among motorcycle couriers.