Objective: The second Gynecologic Cancer InterGroup (GCIG) Endometrial Cancer Clinical Trials Planning Meeting was held on December 1, 2012, and included international multidisciplinary representatives of the 24 member groups. The aims were to review recent advances in molecular pathology of endometrial cancer, focusing on molecular-based therapy, and to identify key hypotheses and issues to be addressed through international collaborative clinical trials. Methods: Reviews and summaries of current knowledge were presented followed by parallelworking group sessions for surgery, adjuvant and systemic therapy, and translational research. Plenary discussions were held to integrate translational and clinical issues, and a final discussion session to agree on key trial concepts. Results and Conclusions: Proposals to take forward on the following trials were agreed: (1) lymphadenectomy to direct adjuvant treatment in women with high-risk endometrial cancer, including a sentinel node substudy; (2) conservative therapy for low-risk endometrial cancers in morbidly obese women with high surgical risks and for fertility-sparing treatment in premenopausal patients; (3) adjuvant therapy for women with early-stage carcinosarcoma. A proposal was made that a GCIG Early Phase Consortium be developed to serve as an international platform for rapid assessment of biomarkers. Copyright © 2013 by IGCS and ESGO.