A computerised, retrospective study of 818 patients with sarcoidosis was analysed to study the prognosis of each individual manifestation of the disease. The good prognosis of erythema nodosum, acute arthritis and bilateral hilar lymphadenopathy was confirmed, though 16 per cent of patients presenting with erythema nodosum pursued a chronic course. Cor pulmonale and nephrocalcinosis reflected the poorest prognosis while lupus pernio and sarcoidosis of the mucosa of the upper respiratory tract rarely resolved. Bone sarcoidosis also implied chronicity but in four of 31 patients there was no clinical evidence of disease activity two years after the initial diagnosis, although naturally the bone radiograph was still abnormal. Hepatomegaly carried a worse prognosis than splenomegaly, or indeed, than the finding of pulmonary mottling without hilar glands--a stage three chest radiograph.