A patient with acute thrombosis of a St. Jude mitral prosthesis was treated with streptokinase with initial success. Subsequent recurrent thrombosis and embolism prompted operative revision. Because the use of thrombolytic agents in this setting is somewhat controversial, we searched the literature for all reports of aortic or mitral prosthetic valve dysfunction treated this way. The cases of 58 patients treated 62 times were reviewed for efficacy of therapy and morbidity. Thrombolytic therapy may be useful in patients with prosthetic valve thrombosis causing critical hemodynamic compromise. It is frequently the only treatment needed. Further, it may help reduce operative risk for those patients in whom complete resolution is not possible. The incidence of systemic embolism is 18%, however, neurological events are usually limited and transient.