Life-threatening situations in sarcoidosis are extremely rare. They may be due to failure of vital organs--lungs, heart, kidney, liver and brain--and usually due to irreversible fibrosis. Respiratory failure follows irreversible pulmonary fibrosis and the development of cor pulmonale. Cardiac sarcoidosis is more sinister for it may be silent, ill-recognised with sudden death or high morbidity. It needs sophisticated techniques to uncover this latent iceberg. Renal failure may be due to granulomatous interstitial nephritis and/or nephrocalcinosis. Hepatic failure is due to intrahepatic cholestasis, portal hypertension and bleeding oesophageal varices. Neurosarcoidosis carries a mortality of 10 per cent, over twice that of sarcoidosis overall. The treatment of each situation is discussed including organ transplantation.