OBJECTIVE: This study aimed to analyze the clinical characteristics and diagnostic features of ovarian fibromatous masses. MATERIALS AND METHODS: The authors reviewed the records of 23 women who underwent laparotomic surgeries and whose final histopathological diagnoses were ovarian fibroma, cellular fibroma, or fibrothecoma from January 2005 to January 2013. The clinical, ultrasonographic, magnetic resonance imaging, tumor marker, therapeutic, and histologic data were analyzed. RESULTS: The mean age of the patients was 50.9 years. Sixteen patients were menopausal. The preoperative ultrasonography examination incorrectly diagnosed seven lesions as uterine fibromas, and the magnetic resonance imaging examination incorrectly labeled three lesions as pedunculated subserous uterine fibromas. The cancer antigen-125 levels of 17 cases were measured, with four being abnormal. Twenty-three patients underwent a laparotomy. Twenty patients underwent a total hysterectomy with bilateral salpingo-oophorectomy, and three underwent a tumorectomy. The histological diagnosis was fibrothecoma in 21 cases, fibroma in one case, and cellular fibroma in one case. Histopathologic examination of the endometrium of seven of the 20 patients who underwent hysterectomy revealed simple endometrial hyperplasia without atypia. CONCLUSION: Ovarian fibromas and fibrothecomas are often misdiagnosed as uterine fibromas and occasionally mistaken for malignant tumors of the ovary preoperatively. As these tumors originate from ovarian stroma, they may be hormone-active tumors. Therefore, they may lead to premalignant changes in the endometrium. The preoperative evaluation of the endometrium is recommended.