There are few reports of pregnancy complicated by a primary borderline paraovarian tumor. A 37-year-old woman after four pregnancies was found to have an adnexal tumor. At 17.4 weeks of gestation, laparotomic right salpingo-oophorectomy was performed and a diagnosis of primary borderline paraovarian serous tumor was made. At 40 weeks of gestation a spontaneous vaginal delivery was performed. Currently, the patient is being followed after the initial surgical treatment and all imaging data show no evidence of recurrence. This case demonstrates the appropriate management for a primary borderline paraovarian tumor during pregnancy.