Thrombotic obstruction of aortic bioprostheses is rare. Few cases have been reported involving the use of the Carpentier-Edwards (CE) prosthesis, the Hancock bioprosthesis, or the Medtronic Intact porcine valve. Thrombolytic therapy for mechanical valve thrombosis has been used frequently even though it is known to carry a high risk of embolism and recurrence. However, the use of this therapy was reported for the first time only recently, in a case of acute aortic thrombosis which occurred 3 1/2 months after bioprosthesis insertion. We report a case of late progressive thrombotic obstruction of a CE aortic valve 3 years after insertion. The case was successfully treated with coumadin therapy, as confirmed by serial Doppler echocardiographic examinations and a 3-year follow-up.