material and methods: we analyzed retrospectively the medium term mortality index in 113 patients with mitral regurgitation diagnosed clinically and echocardiographic who have undergone clinical or surgical treatment since january 1995 until december 1998. the age ranged from 29 to 67 years (mean 47 ± 4.3 years ) and 81 (71.7%) patients were female. in nyha classification, 51 (45.1%) patients belonging to functional class i, 24 (21.3 %) class ii 21 (18.6%) class iii and 17 (15 %) class iv. results: after 4 years we observed that the mortality rate was 21.2%. all the 75 (66.4%) patients belonging to fc (nyha) i and ii, who received only clinical treatment presented mortality rate of 12%. from the 38 patients belonging to fc (nyha) iii and iv, 18 (47.4 %) were submitted to surgical treatment and showed mortality rate of 22.2%: (5.5% surgical mortality and 16.7% during 4 years). the 20 (52.6 %) patients that refused the surgery and presented similar clinical conditions to those operated, were treated clinically and demonstrated mortality rate of 55%. conclusion: we conclude that the mitral regurgitation exhibit high mortality rate and that surgical treatment to the patients belonging to fc ( nyha) iii and iv reveals low mortality rate medium term when compared with clinical treatment.