A metropolitan population of 238000 in Perth, Western Australia, was screened for chronic ulceration of the leg. Patients with a chronic leg ulcer and a venous abnormality comprised 57 per cent of all patients with a chronic leg ulcer, giving a prevalence of 0·62 per 1000 population. There was an increasing prevalence with age; 90 per cent of patients were 60 years and older. This group comprised 16·7 per cent of the population, and had a prevalence of 3·3 per 1000. Although chronic venous ulcers were more common in women there was no difference in age related prevalence. In 36 per cent of patients with a venous abnormality, there was at least one other aetiological factor contributing to chronic ulceration of the leg; 96 per cent had either a history of deep venous thrombosis or a condition known to predispose to deep venous thrombosis.