T2-weighted MR images of the uterine corpus in reproductive-aged individuals typically reveal a three-layered structure. This includes the endometrium, the junctional zone, and the outer myometrium, exhibiting high, low, and intermediate signal intensities, respectively. The endometrium undergoes morphological and functional changes throughout the menstrual cycle. In the menstrual phase, the endometrium is thin, and menstrual blood inside the uterine cavity may be identified as a low signal-intensity area on T2-WIs. During the proliferative (follicular) phase, the endometrium starts thickening. During the secretory (luteal) phase, the endometrium reaches its maximum thickness and appears slightly decreased and homogeneous in signal intensity on T2-WIs, though sometimes, a layer with marginally lower signal intensity, closer to the myometrium, and a layer with higher signal intensity, closer to the cavity, are displayed, or a midline linear area with low to iso signal intensity appears. It is crucial to differentiate endometrial lesions from menstrual bleeding or the thickened endometrium during the secretory phase. It is advantageous to evaluate endometrial images with the menstrual cycle at the time of MR imaging in mind. Evaluations from multiple cross-sections can occasionally be beneficial. The detection of a lesion becomes straightforward if characteristic imaging findings indicative of specific endometrial or intracavitary lesions are observed.