From 1986 to 1992 102 mitral valve repairs were done for mitral regurgitation due to a degenerative disease. Forty-eight patients had an anterior prolapse or prolapse of both leaflets at initial presentation and underwent chordal transposition from the mural leaflet to the anterior leaflet. The corrective procedure was completed by polytetrafluoroethylene or pericardial posterior annuloplasty. Operative mortality was 2.9%, and follow-up (average 22 months) was 100% complete. There were three postreconstruction valve replacements (one earlier and two later) for a probability of freedom from reoperation of 91.5% +/- 5.2% at 3 years. Freedom from all morbidity was 85.5% +/- 5.5% at 3 years. Postoperative echocardiographic studies demonstrated a good mitral valve function: (1) Eighty-seven percent of patients presented no or mild residual regurgitation; (2) transmitral flow indexes were within the norm; (3) left ventricular outflow tract flow was normal in all patients. This study shows that chordal transposition is a safe and effective technique for prolapse of anterior or both leaflets and improves the chances of repair in patients with mitral degenerative disease.