Endometrioma is a common clinical condition, but cases in which an episiotomy scaris present are, however, rare: only two cases have been reported in obstetric journals, and one other in a radiologic journal. All three were in English. We encountered a case in which a solitary endometrioma was present in the perineal region beneath an episiotomy scar. An irregularly marginated hypoechoic mass was revealed by US, and a discrete homogeneous enhancing mass by CT.