Objective: This study aims to evaluate the correlation of intraoperative and definitive diagnosis in high-risk endometrial carcinomas, and percentages of compliance or non-compliance of intraoperative examination in high-risk endometrial carcinoma cases. Material and Methods: In this retrospective study, the pathology archives of our center were evaluated and 90 high risk endometrial carcinoma cases that were examined intraoperatively, between 2005-2017 were analyzed. The following criteria were used to identify high-risk endometrial carcinoma cases: Grade 3 endometrioid carcinomas with lymphovascular invasion and/or myometrial invasion of more than half, tumors of stage 2, 3, 4 and non-endometrioid endometrial carcinoma. Results: Histopathological subtyping was accurate in 52 of the 57 cases of endometrioid carcinoma, 3 of the 20 cases of serous carcinoma and 1 of the 4 cases of clear cell carcinoma. None of the patients diagnosed with mixed carcinoma were accurately diagnosed in frozen section. When results of intraoperative and permenant evaluations were compared; 74.4% of the cases were compatible for histopathological subtype, 76.7% for grade, and 77.7% for myometrial invasion. Conclusion: In patients with high-risk endometrial carcinoma without a preoperative diagnosis, intraoperative evaluation is essential for determining prognostic parameters and performing surgical staging intraoperatively. Despite the careful evaluation of pathologists, the error rate is high in intraoperative evaluation of high-risk endometrial carcinomas. In order to minimize the error rate, both gross and microscopical assessment should be performed with utmost care.