Ninety consecutive patients underwent mitral valve repair for mitral regurgitation (MR) utilizing intraoperative transesophageal echocardiography (TEE). Fifty-nine males and 31 females between the ages of 31 and 88 with a mean age of 67.9 years were evaluated. Preoperative TEE demonstrated pathology involving the posterior leaflet in 28 patients, anterior leaflet in 21 patients, both leaflets in 19 patients, annular dilatation in 19 patients, and restricted leaflet in three patients. Surgical procedures attempted included quadrangle resection of posterior leaflet pathology (40), Duran "flip over" operation (13), or Goretex suture for anterior leaflet pathology (20), and ring alone for central/ischemic mitral regurgitation (20). TEE immediately following repair showed either no regurgitation or a trace in 78 patients (86%). Time elapsed since repair ranged from one month to 55 months, with a mean of 29 months. Long-range evaluation of mitral valve competence was done by clinical examination and transthoracic or transesophageal echocardiography. Three patients died postoperatively. Fifty-six of 87 patients (64%) had either no or trivial MR within the first year of follow-up. Ring alone for annular dilatation and Goretex suture for anterior leaflet prolapse had the highest incidence of progression of MR. Among the 65 patients followed over one year, 42 (64%) continue to have either none or trivial MR. Three patients had worsening MR requiring mitral valve replacement. Quadrangle resection for posterior leaflet repair and Duran "flip over" operation for anterior leaflet pathology had the highest success rate in long-term follow-up.