The sleep apnoea/hypopnoea syndrome has been reported to be rare in Britain. We have offered a clinical service for the diagnosis and treatment of this condition in Scotland for four years during which there has been an increase in referral rate from 19 patients in year 1 to 61 in year 4. We report the clinical features of the 80 patients. Seventy-eight snored and 70 were somnolent, each falling asleep at least once each day when not in bed. Ten reported falling asleep whilst driving or flying. Twenty-nine slept restlessly, 28 were not refreshed by sleep and 21 had nocturnal choking attacks. Ankle swelling was reported by 26 and 25 were hypertensive (diastolic BP greater than 95 mmHg). Two had hyperthyroidism and one acromegaly. Nineteen have been successfully treated by continuous positive airway pressure therapy at home. The data suggest that regional centres should be established in Britain to diagnose and treat this condition.