Thrombosis of a bileaflet mechanical heart valve is life-threatening, and surgical thrombectomy of the prosthesis is appropriate in selected patients. Five patients (three men, two women; average age 56 ± 1 years; range: 56 to 66 years) with thrombosis of left-sided bileaflet mechanical valves underwent videoassisted thrombectomy of the prosthesis. Four patients had thrombosis of a bileaflet mitral mechanical valve, and one patient had thrombosis of an aortic valve prosthesis. Preoperatively, patients were in either NYHA functional class IV (n = 4) or class I (n = 1). Surgery was performed through a right anterior thoracotomy or a median sternotomy. A rigid 30[deg] thoracoscope was inserted into the left atrium or aorta to visualize the thrombosed valve. The thrombus was extracted and the prosthesis under-surface examined and cleaned. Leaflet mobility, assessed with transesophageal echocardiography, was normal following surgical thrombectomy. Mean cardiopulmonary bypass time was 102 ± 30 min; mean aortic cross-clamping time was 47 ± 25 min. There was no hospital mortality; mean hospital stay was 9 ± 1 days (range: 6 to 11 days). Anticoagulation with intravenous heparin was resumed 24 h after surgery. Three patients were discharged on coumadin treatment alone and two on aspirin plus coumadin. Mean follow up was 7 ± 8 months (range: 1 to 21 months). One patient died 21 months after thrombectomy of a mitral prosthesis; the unconfirmed diagnosis was recurrent mitral valve dysfunction. At 1-15 months after surgery, four patients are in NYHA class I, without evidence of prosthesis dysfunction. To conclude, videoassisted thrombectomy of a bileaflet mechanical heart valve is a treatment option in patients with acute thrombosis of the prosthesis.