Benign multicystic peritoneal mesothelioma (BMPM) is rare and difficult to diagnose before surgery. We report a case of BMPM incidentally discovered during laparoendoscopic single site surgery (LESS) for treatment of a pelvic mass. A 47-year-old Korean menopaused woman presented to our outpatient clinic with a pelvic mass. She had a history of right ovary cystectomy with adhesiolysis at a local hospital in 2010. Imaging study of the pelvis revealed a multilocular cystic mass. LESS was performed and multiple grapelike clusters of cysts were seen in the uterus, cul-de-sac, both adnexa, pelvic wall, and omentum. The appendix was grossly free. Frozen biopsy confirmed BMPM. Excision of multiple cyst clusters of cysts, resection of the uterus with both adnexa, appendectomy, omentectomy, and adhesiolysis were performed with LESS. She is well for 2 years with no recurrence. BMPM should be included in the differential diagnosis when small multichamber cystic mass is found on ultrasonography.