Background. This report describes technical details of the right thoracotomy approach for mitral surgery, and analyzes our experience with this procedure for patients with a prior sternotomy. Three methods for myocardial management (hypothermic cardioplegic arrest, beating heart, and fibrillating heart) are compared. Methods. Records were abstracted of patients who had a right thoracotomy between January 1, 1992 and July 1, 1999 for mitral surgery after at least one prior sternotomy. Demographic, operative, and outcome data were collected for analysis. Telephone follow-up was used to measure postoperative New York Heart Association functional status. Results. Eighty-four patients (mean age 60 ± 15 years) had reoperative mitral surgery via a right thoracotomy. Myocardial management included ventricular fibrillation in 10 patients, operation on the beating heart in 58 patients, and hypothermic blood cardioplegia arrest in 16 patients. The mean time in the operating room was 185 ± 73 minutes, and the mean duration of cardiopulmonary bypass was 63 ± 56 minutes. There were no perioperative strokes and the prevalence of death for patients who received cardioplegic arrest was significantly higher than the prevalence of death for patients who had mitral surgery with perfused fibrillating or beating heart techniques (p = 0.007; Fisher's exact test comparing risk-unadjusted mortality). Conclusions. Right thoracotomy provides efficient exposure for reoperative mitral surgery. Mitral valve procedures on the fibrillating or beating heart are feasible in most patients and are at least as safe as surgery using cardioplegic arrest. © 2000 by The Society of Thoracic Surgeons.