Abstract Between 1967 and 1979, 411 patients underwent surgical treatment of isolated mitral stenosis at our institution. Open radical mitral commissurotomy was performed in 150 patients (1967–1978; mean follow-up, 46 months; range, 4 to 116 months). Mitral valve replacement using a porcine prosthesis was performed in 74 patients (1976–1979; mean follow-up, 23 months; range, 2 to 48 months). Mitral valve replacement with a cloth-covered Starr-Edwards prosthesis was performed in 187 patients (1967–1975; mean follow-up, 45 months; range, 2 to 106 months). Preoperative characteristics were similar in the three groups. The open commissurotomy and Starr-Edwards groups were followed up to 9 years and the porcine valve group up to 4 years, with 97% follow-up in each group. Life-table analysis (6-month intervals) of all postoperative complications revealed significantly greater complication-free survival for patients who had open radical commissurotomy compared with Starr-Edwards ( p < 0.05) valve replacement. Similar analysis of thromboembolic and warfarin-related complications revealed significantly fewer complications in commissurotomy patients. No significant differences were found ( p > 0.05) when comparing the need for subsequent reoperation in each group. Operative mortality following open radical mitral commissurotomy (0%; 0 out of 150) was significantly less ( p < 0.05) than after mitral valve replacement in both porcine (8.1%; 6 out of 74) and Starr-Edwards (11.2%; 21 out of 187) groups. Life-table analysis of late cardiac-related mortality revealed a significantly greater cumulative survival rate for the commissurotomy versus the Starr-Edwards groups at all intervals from 12 to 108 months (100 versus 84 ± 5%, p < 0.05). No significant differences were noted between commissurotomy and porcine valve groups during the 4-year follow-up period (100 ± 0% versus 96 ± 3%, p > 0.05). Based on these findings, we conclude that when the anatomy is favorable, the surgical treatment of choice for isolated mitral stenosis is open radical mitral commissurotomy.