Endometrial cancer comprises a heterogeneous group of tumors, with distinct risk factors, clinical presentation, histopathological features and molecular characteristics. Currently, treatment of metastatic or recurrent disease is based on conventional chemotherapy combination regimens. Advances in the understanding of the molecular pathology of the two types of endometrial carcinoma--type I (endometrioid) and type II (non-endometrioid)--have underpinned the first steps in the development and testing of targeted therapies. Of the potential therapeutic targets identified to date, clinical trials have only assessed the efficacy of inhibition of the EGFR, VEGFR and PI3K/PTEN/AKT/mTOR signaling pathways; responses to these targeted therapies were modest. Despite the striking molecular differences between type I and type II endometrial cancers, most clinical trials have not taken this diversity into account. The identification of activating mutations of kinases (for example PIK3CA and FGFR2) and loss of function of genes related to DNA repair (for example PTEN) may lead to more biology-driven clinical trials exploiting the concepts of oncogene addiction and synthetic lethality.