The objective of the present study was to examine the independent contribution of symptoms of obstructive sleep apnoea syndrome (OSAS) to long-term sick leave and permanent work disability. Using a historical cohort design with 4 yrs of follow-up, information on sick leave and disability benefit recipiency were merged with health information from the Hordaland Health Study, carried out in western Norway during 1997-1999. Persons aged 40-45 yrs (n = 7,028) were assessed for self-reported symptoms of OSAS (snoring, breathing cessations and daytime sleepiness), body mass index, somatic conditions and other potential confounders. The outcomes, cumulative sick leave of > or =8 weeks and permanent work disability, were identified in records from the National Insurance Administration. After excluding participants with work disability at baseline, symptoms of OSAS were found to be a significant predictor of both subsequent long-term sick leave and permanent work disability. These effects remained significant after adjustment for a range of possible confounding factors. Daytime sleepiness showed the greatest explanatory power, followed by breathing cessations and snoring. It is concluded that self-reported symptoms of obstructive sleep apnoea syndrome are an independent risk factor for subsequent long-term sick leave and permanent work disability. These findings need to be replicated using objective measures of obstructive sleep apnoea syndrome.