An investigation of 78 cases of adrenal haemorrhage and necrosis disclosed that 32 were examples of adrenal venous infarction. In all these cases there was thrombosis of the main adrenal vein and in most there was also thrombosis of the capsular veins, a finding which has not been well established. In a number of cases with venous infarction there was clinical and pathological evidence that disseminated intravascular coagulation (DIC) had occurred, but it appears that it was not the direct cause of venous thrombosis. The majority of cases of venous infarction occur in patients with severe infection, frequently of the respiratory tract. Venous infarction was found in five cases with hypothermia an association which had rarely been described, and in three of these there was evidence of DIC. This is apparently the first occasion on which DIC has been demonstrated in cases of hypothermia in man. The cause of venous thrombosis in the adrenal glands is obscure in most cases of venous infarction, although in three it was due to involvement by metastatic carcinoma. It is suggested that the factors responsible for the initiation of thrombosis in the adrenal veins are catecholamines, thrombin, fibrin and endotoxin. Localisation of the thrombi to the adrenal vein is due to the unique anatomical structure of the vein which, under certain circumstances, results in the local stasis of blood.