Endometrial carcinoma is a malignant epithelial tumor that forms in the inner lining, or endometrium, of the uterus. Endometrial carcinoma is the most common gynecologic malignancy. Approximately two-thirds of endometrial carcinoma cases are diagnosed with disease confined to the uterus. The complete NCCN Guidelines for Uterine Neoplasms provide recommendations for the diagnosis, evaluation, and treatment of endometrial cancer and uterine sarcoma. This manuscript discusses guiding principles for the diagnosis, staging, and treatment of early-stage endometrial carcinoma as well as evidence for these recommendations.