We gave cryoprecipitate to six patients with uremia and bleeding times prolonged to more than 15 minutes. After the infusion, all patients had shortened bleeding times; the times of five became normal. In four patients control of major bleeding episodes was attained, and five underwent major surgical or invasive procedures, with good hemostasis. After infusion the time before the nadir of the bleeding time was reached was between one and 12 hours. The bleeding time returned to pretreatment levels by 24 hours after infusion in five patients, and by 36 hours in the other patient. Platelet-aggregation studies before infusion gave normal results in three patients and abnormal results in three. There wasno change after infusion. Before infusion, levels of Factor VIII coagulant activity and Factor VIII von Willebrand activity were normal, Factor VIII-related antigen was increased, and crossed immunoelectrophoresis of Factor VIII-related antigen was normal. Our findings suggest that cryoprecipitate can temporarily correct the bleeding tendency in patients with uremia.