5 cases of unilateral and 3 cases of bilateral haemorrhage are described. Only 1 infant died, from venous thromboses elsewhere. Apart from this case, all had an above average birthweight. Probable predisposing causes apart from large size were fetal hypoxia, septicaemia, thrombocytopenia, coagulation defect, and disseminated thromboembolic disease. The condition must be distinguished from renal vein thrombosis. In the acute stage pyelography shows depression of the kidney on the affected side, with flattening of the upper calyces. Calcification develops rapidly round the periphery of the mass, then slowly contracts into an area of the size and shape of the original gland. Treatment is with antibiotics and blood transfusion, with intravenous corticosteroids in severely shocked or bilateral cases. Adrenal insufficiency is rarely found on follow-up even in bilateral cases, but renal hypertension should be looked for. No single cause for the haemorrhage could be discovered, but the preponderance of haemorrhage into the right adrenal gland is probably due to anatomical differences between the venous drainage of the two sides.