Introduction. Borderline ovarian tumors are non-invasive neoplasms characterized by atypical epithelial proliferation and increased levels of mitotic activity, "on the border" between benign and malignant ovarian tumors. These tumors are usually diagnosed at an early stage and only 25% of cases are in stages II-IV. Their survival is better than that of ovarian cancer, in the early stages being about 83-91% at 10 years. Case report. 28-yearold, nulliparous patient, prophylactic gynecological ultrasonographic examination revealed a 4cm ovarian mass with papillomatous growths, immunologically CA125- 23.2, HE4-75.1, Rome Score 17.9 (N- <11.4). An ovarian mass on the right with suspicion of malignancy is confirmed at resonance. She underwent volume-conservative surgical treatment of ovarian cystectomy on the right side without breaking the tumor capsule, with a biopsy from the peritoneum and omentectomy. Histopathological and immunohistochemical examination: serous borderline ovarian tumor without peritoneal metastases, moderate p53positive, moderate ER-positive, pronounced PRpositive, Ki-67-positive 2%. Dynamically evaluated over 3 and 5 years, she gives birth to two perfectly healthy children with no signs of progression at the moment. Conclusion. The role of conservative treatment for borderline tumors is to preserve the reproductive function of the woman, their evolution is unpredictable, but in cases with favorable evolution is reported, the possibility of ovarian cystectomy instead of adnexectomy and when invasive peritoneal implants are not confirmed, and if the patient wants to preserve her fertility. The prognosis is good, being approximately 83-91% at 10 years, but the recurrence cycle is long.