Clues as to the reason for hemorrhagic phenomena among uremic patients were sought in a study of 65 men whose blood urea nitrogen levels were either above 24 mg. per 100 ml. or fluctuating about uremic levels. In 49 of the patients the blood urea nitrogen level was over 50 mg. per 100 ml. A series of tests was done, including the clotting time in glass, clotting time in silicone-treated glassware, one-stage prothrombin time, prothrombin consumption, platelet count, and, in some cases, thromboplastin generation, clot retraction, and capillary fragility. No impairment of clot retraction could be demonstrated in any of the patients, and no single test gave consistently abnormal results in these patients. There was, however, a rough correlation in that more of the tests gave abnormal results at the higher levels of uremia.