Unlike borderline ovarian tumors, paratubal borderline tumors are extremely rare gynecologic tumors. They occur in reproductive-aged females at an earlier stage of disease and have a good prognosis. A 61-year-old woman, gravida 3 para 3, presented with progression of ovarian cyst. Computed tomography revealed a 6-cm simple cystic lesion without enhancing papillary projections. The patient underwent total laparoscopic hysterectomy and bilateral salpingo-oophorectomy. Frozen specimens showed that the tumor was benign, thereby confirming a final diagnosis of paratubal borderline serous tumor. The patient refused comprehensive surgical staging and opted for close follow-up. The patient remains asymptomatic with no evidence of recurrence at the 24-month follow-up. To the best of our knowledge, this is the first reported case of paratubal borderline serous tumor in a postmenopausal patient. The findings of this study and those of other case reports can contribute to the understanding, diagnosis, treatment and prognosis of these rare tumors.