Objective: The aim of this study was to assess tumor markers and clinicopathological findings of patients with serous and mucinous borderline ovarian tumor (BOT) features. Methods: The study consisted of 50 patients that were diagnosed with and treated for BOT between 2005- 2010 in three centers. CA125, CA19-9, and CA125+CA19-9 levels and clinicopathological features were compared in serous and mucinous histotypes. In serous and mucinous BOTs, correlations between tumor markers and demographics such as age, menopausal status, parity, clinical findings (stage, relapse, adjuvant chemotherapy, cytology, lymph node involvement and tumoral morphology (cystic-solid content, papilla, septation) were evaluated. Results: There were no significant differences between serous and mucinous tumors in the clinicopathological features such as stage, tumor markers, age, menopausal status, or cytology. In serous BOTs we found a significant relation between elevated CA 125+ CA 19-9, CA 19-9 and recurrence (p<0.05). Also there was a significant relation between elevated CA 125+ CA 19-9, CA 19-9 and cytology positivity (p<0.05). We found a significant relation in serous BOTs between elevated CA125+CA19-9, adjuvant chemotherapy and lymph node metastases (p<0.05). Also In mucinous BOTs with papilla formation we found a significant relation between elevated CA125 and CA 125+ CA19-9 (p<0.05). There was significant relation between cytology positivity and elevated CA 19-9 in mucinous BOTs (p<0.05). Conclusion: Serum tumor markers of serous and mucinous BOTs were different in relation to their clinicopathological features. This may reflect differences of serous and mucinous BOTs.