The prevalence of sleep complaints and somatic diseases was estimated in a random sample of 4064 Swedish men aged 30-69 years. Greater difficulty initiating sleep (DIS) was experienced by 6.9% and moderate problems in DIS by 14.3%. Complaints of major difficulty maintaining sleep (DMS) were reported by 7.5% of the mean and of moderate DMS by 14.9%. DMS was more frequent with increasing age. Excessive daytime sleepiness (EDS) was reported by 5.7%. Altogether 879 men were attending regular medical exmainations for somatic diseases. Among the 299 hypertensive men, major complaints of DMS (13.5%), DIS (8.4%) and EDS (8.8%) were more common, but the 167 men treated with .beta.-blockers rather showed a proportionately somewhat lower prevalence of sleep complaints. Men with obstructive pulmonary disease (n = 113) had a higher prevalence of DMS (18.8%) and EDS (12.4%). Diabetic men (n = 74) complained also more often of DMS (21.9%), DIS (21.1%) and EDS (12.2%). Men with rheumatic disease (n = 176) and obesity (n = 221) also had increased prevalence of sleep complaints.