Background: Ovarian leiomioma (OL) is one of the rarest benign ovarian tumors of mesenchimal origin. OL was firstly described by Sangally in 1862 and, till present, less than 100 cases of OL had been documented and published in specialized literature. During this research, a computer search was performed in PubMed, MedLine and Google Scholar databases using the keywords: ovary, ovarian leiomyoma, benign tumor, organ preserving surgery. According to literature data, OL is more common in women between the age of 20 and 65, and, in 85% of cases, in the premenopausal period. Currently, OL is divided into primary and secondary types. Secondary OL are usually the consequences of uterine leiomyoma and disseminated peritoneal leiomyomatosis, that attaches itself to the ovary. In most cases, OL are small (≤ 3cm) and likewise, there are described giant OL, with dimensions of 25-30 cm. The correct preoperative diagnosis of OL is quite complicated, which is mostly caused by the rarity of the pathology and interpretation of the results of radiological investigations, being wrongly interpreted as subserosal uterine leiomyoma, uterine leiomiosarcoma, leiomyoma of broad ligament of the uterus, fibroma/thecoma, etc. For OL, it is characteristic a benign results with favorable prognosis and a lack of recurrences after surgical treatment – ovarian preserving operations. Conclusions: OL refers to very rare benign tumors. Despite the use of the entire arsenal of imaging methods, the preoperative diagnosis of OL is quite difficult, thus, in patients of childbearing potential, ovarian preserving interventions should be considered justified. Histological study, in combination with immunohistochemistry investigation, is the basic method in the diagnosis of ovarian leiomyoma.