The normal endometrium changes regularly with the menstrual cycle and atrophies after menopause. It is important to be aware of the normal spectrum of endometrial appearances at imaging to accurately detect and diagnose pathologic conditions. This article reviews imaging features of the normal and abnormal endometrium, and conditions which may mimic endometrial pathology. Emphasis will be on ultrasound with sonohysterography and magnetic resonance imaging as these are the imaging modalities of choice for evaluation of the endometrium. The complementary role of hysterosalpingography, computed tomography, and 18-fluorodeoxyglucose-positron emission tomography will also be discussed.