To establish whether snoring and excessive daytime sleepiness (EDS), the main symptoms of obstructive sleep apnea syndrome, influence the risk of occupational accidents a population-based, prospective study was performed. In 1984, 2,874 men aged 30-64 answered questions on snoring and EDS. Ten years later 2,009 (73.8% of the survivors) responded to a follow-up questionnaire including work-related questions and potential confounders. Information on occupational accidents during 1985-1994 was obtained from national register data. A total of 345 occupational accidents were reported by 247 of the men (12.3%). Multivariate analysis revealed that men who reported both snoring and EDS at baseline were at an increased risk of occupational accidents during the following 10 yr, with an adjusted odds ratio of 2.2 (95% CI 1.3-3.8) after adjusting for age, body mass index, smoking, alcohol dependence, years at work, blue-collar job, shift work, and exposure to noise, organic solvents, exhaust fumes, and whole-body vibrations. However, no significant increased risk was found for snorers without EDS or nonsnorers with EDS. We conclude that sleepy, male snorers have an increased risk of occupational accidents. The results indicate that early identification and treatment of sleep-disordered breathing may reduce the number of injuries at work.