Objective: The aim of this study was to evaluate the preoperative tumor marker levels and imaging findings of patients diagnosed with mucinous ovarian tumors and to determine the utility of these parameters as predictors of malignant cases. Materials and Methods: This was a retrospective study involving 20 women with mucinous cystadenocarcinoma and 27 women with mucinous borderline tumor of intestinal type registered between November 1, 2006, and April 30, 2016, and of 47 women with mucinous cystadenoma registered between September 1, 2011, and April 30, 2016. The mucinous ovarian tumors were divided into three groups: benign group, borderline group, and malignant group. Preoperative tumor markers and imaging findings were compared among the three study groups. Results : In patients with definitive diagnoses of benign tumors and malignant tumors, the area under the curve (AUC) of CA125 was the highest, and the AUC of number of septa was second. In patients with definitive diagnoses of mucinous borderline tumors and mucinous carcinomas, the AUC of CA125 was the highest, and the AUC of CA72-4 was second. Conclusion: In mucinous tumors, measurements of CA125 and CA72-4 levels were helpful to distinguish malignant from benign tumors. The number of septa was a significant predictor of malignancy.