The advantages of mitral valve repair in mitral regurgitation are well established. The aim of this study was to analyze retrospectively the early and mid-term results of primary mitral valve repair. Between January 1995 and August 2001, primary mitral valve repair operations were performed on 112 patients (76 men and 36 women) with mitral regurgitation; the mean age was 59.8 +/- 16.5 years. Mitral valve repair was performed for rheumatic heart disease (13), degenerative disease (60), infective endocarditis (2), ischemic heart disease (26), congenital heart disease (2), and dilated cardiomyopathy (9). The degree of mitral regurgitation was moderate in 28 patients, moderately severe in 17 patients, and severe in 67 patients, as determined by echocardiography. Left ventricular ejection fraction (mean 41.2% +/- 13.5%) was measured by radionuclide ventriculography. Fifty percent of patients underwent additional procedures (e.g., coronary artery bypass grafting). The mortality rate was 8.9% (10/112) for hospitalized patients, 19.2% (5/26) for ischemic disease, and 5% (3/60) for degenerative disease. Follow-up duration ranged from 0.37 to 84.03 months. All survivors were evaluated with serial echocardiography. At the final follow-up echocardiography of 94 patients without reoperation and 6 patients at the time of reoperation, 84% had no or mild mitral regurgitation. The survival rate at 5 years was 92.68 +/- 3.57% for degenerative disease and 44.47% +/- 10.89% for ischemic disease. The risk of infective endocarditis (1.78%), thromboembolism (1.78%), and anticoagulant-related complications (0.8%) was very low during the follow-up period. The pathophysiological mechanism resulting in mitral regurgitation was the most important determinant of outcome after mitral valve repair. Excellent results were achieved with mitral valve repair for degenerative disease. Because of low morbidity and acceptable mortality, we strongly recommend mitral valve repair for mitral regurgitation due to degenerative disease.