Short- and long-term results of valve repair for degenerative mitral insufficiency are reported in 127 consecutive patients with a mean age of 57 years (range 25-76). Preoperatively, 32 patients (25%) were in NYHA functional class IV, 65 (51%) in class III, 29 (23%) in class II, and 1 (0.8%) in class I. The mitral lesions and the mechanism of valvular regurgitation were assessed preoperatively by echocardiography (transthoracic and/or transesophageal) and intraoperatively by inspection of the valvular structures. Cardiac catheterization was performed only in 14 patients with some evidence of concomitant coronary artery disease, and critical stenoses were found in 5 cases. The mitral valve prolapse was posterior in 66 cases (52%), anterior in 29 (23%) and of both leaflets in 32 (25%). The posterior prolapse was corrected by quadrangular resection technique. The anterior and both leaflet prolapses were managed by transposition of chordae from the mural leaflet to the prolapsed part of the anterior leaflet. To give more stability to the repair in all cases except one, the valve repair was completed by posterior annuloplasty, using a PTFE 4 mm conduit (73 pts) or an autologous pericardium graft (53 pts). One patient died perioperatively (operative mortality 0.7%) and in only one case (the one in which posterior annuloplasty was not performed) was mitral valve replacement necessary two days after operation, for dehiscence of the valvar reconstruction.(ABSTRACT TRUNCATED AT 250 WORDS)