Surgical resections, such as peritoneal stripping (peritonectomy) are performed for disseminated diaphragmatic lesions of advanced ovarian cancer. This study retrospectively investigated the incidental events of diaphragmatic surgery. The records of patients with advanced mullerian carcinomas, including ovarian, primary peritoneal and fallopian carcinomas, who underwent diaphragmatic surgery were reviewed. Based on our criteria, stripping was performed for surface disease on the diaphragm, and full-thickness resection was performed for bulky disease. In certain cases, both procedures were performed. We analyzed intra- and post-operative incidental events in 82 patients. The χ(2) and Fisher's exact tests were used in the statistical analysis. There were 82 stage III-IV cases of which 56 patients underwent stripping, 12 underwent full-thickness resection and 14 patients underwent both procedures. Unexpected open chest surgery following stripping occurred in 1 out of 63 patients (1.6%) in the primary, 4 out of 13 patients (30.8%) in the interval and 0 out of 6 patients (0.0%) in the secondary debulking surgery groups. The incidence of unexpected open chest surgery was high in the interval debulking surgery group (p<0.001). Regarding post-operative events, accumulation of pleural effusion was identified in 43 patients (52.4%). The incidence of pleural effusions was not significantly different between the two procedures. No complications were encountered, nor was a chest tube required, during unexpected open chest surgery and postoperative pleural effusions. Therefore, it was concluded that special attention should be paid during interval debulking surgery even though it was possible for surgical resections of diaphragmatic lesions to be performed safely.