This work was carried out under the aegis of the CNGOF (Collège national des gynécologues et obstétriciens français) and proposes guidelines based on the evidence available in the literature. The objective was to define the diagnostic and surgical management strategy, the fertility preservation and surveillance strategy in Borderline Ovarian Tumor (BOT). No screening modality can be proposed in the general population. An expert pathological review is recommended in case of doubt concerning the borderline nature, the histological subtype, the invasive nature of the implant, for all micropapillary/cribriform serous BOT or in the presence of peritoneal implants, and for all mucinous or clear cell tumors (grade C). Macroscopic MRI analysis should be performed to differentiate the different subtypes of BOT: serous, seromucinous and mucinous (intestinal type) (grade C). If preoperative biomarkers are normal, follow up of biomarkers is not recommended (grade C). In cases of bilateral early serous BOT with a desire to preserve fertility and/or endocrine function, it is recommended to perform a bilateral cystectomy if possible (grade B). In case of early mucinous BOT, with a desire to preserve fertility and/or endocrine function, it is recommended to perform a unilateral adnexectomy (grade C). Secondary surgical staging is recommended in case of serous BOT with micropapillary appearance and uncomplete inspection of the abdominal cavity during initial surgery (grade C). For early-stage serous or mucinous BOT, it is not recommended to perform a systematic hysterectomy (grade C). Follow up after BOT must be pursued for more than 5 years (grade B). Conservative treatment involving at least the conservation of the uterus and a fragment of the ovary in a patient wishing to conceive may be proposed in advanced stages of BOT (grade C). A new surgical treatment that preserves fertility after a first non-invasive recurrence may be proposed in women of childbearing age (grade C). It is recommended to offer a specialized consultation for Reproductive Medicine when diagnosing BOT in a woman of childbearing age. Hormonal contraceptive use after serous or mucinous BOT is not contraindicated (grade C).