Aim: To determine utility of the frozen section (FS) in the operative management of endometrial pre-malignant lesions. Materials and Methods: We retrospectively analyzed patients who underwent abdominal hysterectomy with preoperative diagnosis of complex atypical endometrial hyperplasia (CAEH) and simple endometrial hyperplasia (SEH) between May 2007 and December 2013. Frozen and paraffin section (PS) results were compared. Sensitivity, specificity, the positive predictive value (PPV), the negative predictive value (NPV) and the accuracy in predicting EC on FS were evaluated with 95% confidence intervals (CIs) for each parameter. The correlation between FS and PS was calculated as an κ coefficient. Results: Among 143 preoperatively diagnosed CAEH cases, 60 (42%) were malignant and 83 (58%) were benign in PS; and among 60 malignantcases diagnosed in PS, 43 (71%) were “malignant” in FS. Sensitivity, specificity, PPV and NPV for FS were 76%, 100%, 100% and 87.5%, respectively. Conclusions: We found that FS is reliable and applicable in the management of endometrial hyperplasias. It is important that the pathologist should be experienced becauseFS for endometrial pre-malignant lesions has significant inter-observer variability. The other conclusion is that patients with the diagnosis of EH, especially those who are postmenopausal, should undergo surgery where FS investigation is available.