The right atrial trans-septal approach is one approach to the mitral valve. We used this approach in 25 patients from October 1990 to May 1993. Fourteen patients were in NYHA class II, 10 in class III and 1 in class IV. All had gross cardiomegaly with a left atrial dimension of 58±14 mm. The majority had advanced rheumatic heart disease involving more than 1 valve and therefore needed double or triple valve repair or replacement. A total of 49 operative procedures were performed, that is, about 2 per patient. The procedures for the mitral valve included open mitral valvotomy in 3 patients, valve repair in 12 patients and valve replacement in 10 patients. The average cross-clamp time was 84±14 min. No patient died while in hospital. Each heart maintained its preoperative rhythm (sinus in 13 cases and atrial fibrillation in 12 cases). None developed iatrogenic arrhythmia or conduction defect. There was no residual atrial septal defect. This approach is useful, safe and convenient.