This study reports on the experience gained by using transesophageal echocardiography (TEE) in patient selection for thrombolytic therapy in prosthetic mitral valve thrombosis. Twenty-nine consecutive patients with prosthetic mitral valve thrombosis were screened with TEE for thrombolytic therapy, and 21 underwent thrombolytic treatment. Thrombolysis was successful in 17 (81%) patients, and partially successful in three (14%); treatment failed in one (5%) patient. Two (9%) cases of skin bleeding, and one case (5%) of non-fatal embolic stroke were seen as complications of treatment. It was concluded that TEE guidance of thrombolysis might reduce, but not eliminate, the risk of thromboembolic complications. The response to thrombolytic therapy became apparent in 24 h; however, extension of treatment beyond this time provided no additional short-term benefit.