Over a 23-year period 497 patients with sarcoidosis were seen at Willesden Chest Clinic, of whom 151 were British, 105 Irish, 165 West Indian, and 35 Asian. The estimated annual incidence was: British 4/100,000, Irish 21/100,000, West Indian 58/100,000 and Asian 14/100,000. There was a marked female preponderance in the Irish (65 per cent) and West Indians (57 per cent). The female mean age was 35 years, the male mean age 32 years. Asian and West Indian patients were older (mean 37 and 38 years) and Irish patients younger (mean 29 years). West Indian patients more frequently had involvement of the less common extrathoracic sites. In 402 patients the outcome was known: 64 per cent of patients recovered within five years but proportionally fewer West Indians (55 per cent) and Asians (48 per cent) recovered. The greater morbidity in the West Indian and Asian patients was particularly associated with extrathoracic disease in which the results were poor.