Objectives: To evaluate the predictive value of preoperative CA125 in extra-uterine disease and its association with poor prognostic factors in endometrioid-type endometrial cancer (EC). Material and methods: A total of 423 patients with pathologically proven endometrioid-type EC were included in the study. The association between preoperative CA125 level and surgical-pathological factors was evaluated. The conventional cutoff value was defined as 35 IU/mL. Results: A high CA125 level (> 35 IU/mL) was significantly associated with all of the studied poor prognostic factors, except grade. The risk of lymph node metastasis (LNM) increased from 15.9% to 45.7% when CA125 level was > 35 IU/mL (p < 0.05). The optimal cutoff value for the prediction of LNM in patients aged > 50 years was determined to be 16 IU/mL (sensitivity, specificity, positive predictive value, and negative predictive value were 71%, 60%, 35%, and 87%, respectively.) Conclusions: Preoperative CA125 level was significantly related with the extent of the disease and LNM. The age-dependent cutoff level of CA125 can improve the prediction of LNM in endometrioid-type EC. For older patients, CA125 level of > 16 IU/ml could be used to predict LNM. However, further studies are needed to evaluate the appropriate cutoff level of CA125 for younger patients.