We examined the surgical procedure and long-term results in patients who underwent intraoperative re-do for the completion of mitral valve repair. Between March 1993 and July 1996, 81 patients underwent mitral valve repair for pure MR using TEE evaluation. Of these, 12 patients that were judged to have more than mild residual regurgitation (MRA≥2.0cm² or MRL≥1.0cm) underwent intraoperative re-do. All of the patients were type 2, according to Carpentier's classification. Seven patients had degenerative disease and 2 had infective endocarditis. If the cause of residual MR was localized discoaptation, 5-0 suture plication with beating heart that increased the coaptation zone and resulted in decrease in the residual MR was useful. If the cause of residual MR was leaflet prolapse or dehiscence, intraoperative re-do was performed the cardiac re-arrest. Two patients of billowing valve underwent MVR and the other needed additional resection of leaflet, artificial chorda or suture. After intraoperative re-do, every procedure resulted in a reduction of MR except for 2 patients underwent MVR during the early postoperative stage, and of those all but one remaine no-to-mild MR in the late term (mean follow-up 26.2 months). In conclusion, 5-0 suture plication was effective for intraoperative re-do procedures, and basic mitral valve repair modification was necessary in about half of the cases. Intraoperative re-do was safely performed with no mortality or morbidity and it yielded good long term results. Intraoperative TEE evaluation was considered to be important.