Endometrial carcinoma, a common malignancy of the female genital tract, is composed of a number of tumor types with different light-microscopic features, molecular genetic alterations, and prognoses. In addition, hormonal influences significantly impact growth regulatory pathways and interact with genetic alterations in the pathogenesis of at least some types of endometrial carcinoma. These factors have complicated the analyses of endometrial carcinoma, but over the past decades, awareness of the different types of endometrial carcinoma, in addition to careful clinicopathological studies, molecular analyses, and animal studies of the biological underpinnings of the different tumor types, has increased. We present the current understanding of endometrial carcinoma, from a molecular vantage point, highlighting what are presently thought to be the fundamental pathways involved in the development and progression of the major types of endometrial carcinoma.