Carpentier's techniques of prosthetic ring mitral valve repair for mitral regurgitation offer the potential for immediate and long-term improvement in valve function without the necessity of replacing the native valve with a prosthesis. A consecutive, case-matched series of 65 patients with prosthetic ring mitral valve repair was compared with 65 patients undergoing mitral valve replacement for mitral regurgitation. The aortic cross-clamp time was 57 +/- 33 minutes in the repair operations and 41 +/- 25 minutes in the replacement operations (p = 0.003). The cardiopulmonary bypass time was 154 +/- 44 minutes in the repair operations and 113 +/- 41 minutes in the replacement operations (p = 0.0001). There were no myocardial infarctions in the hospital in either group. Hospital death was noted in 1.5% of repairs and 4.6% of replacements (p = not significant). Survival at 4 years was 0.84 for repairs and 0.82 for replacements (p = not significant). Freedom from reoperation to replace the mitral valve at 4 years was 62 of 65 patients in the repair group and 64 of 65 patients in the replacement group (p = not significant). In-hospital and midterm results in a closely matched population show that mitral valve repair yields results comparable with those of replacement despite a more difficult procedure. The benefits of maintaining the native valve with chordal and papillary muscle structure intact and avoidance of prosthetic valve implantation may then become apparent with longer follow-up.