Around 10–15 % of epithelial ovarian cancers have histological and clinical behavior that are intermediate among benign and malignant tumors. These low malignant potential (LMP) tumors, also called borderline, were firstly described by Taylor in 1929. These neoplasms have a more favorable outcome than malignant ovarian cancers, but they were considered comprehensively by the International Federation of Gynecology and Obstetrics (FIGO) and the World Health Organization (WHO) until the early 1970s. Although LMP tumors may develop at any age, patients are usually in their 40s, about 15–20 years younger than women with invasive ovarian cancer, and the large majority of LMP tumors is discovered at stage I. Surgery is the treatment of choice, and the conservative strategy is strongly increasing in the last years. They often have a good prognosis, but because of many reasons, their management is frequently problematic.