MRI provides precise visualization of myometrial zonal anatomy. Physiological uterine contractions can be well seen at MRI, sometimes mimicking pathologies such as adenomyosis. The latter is a frequent condition related to the presence of endometrial tissue within the myometrium that can be asymptomatic or cause menorrhagia, pelvic pain, and infertility. The presence of cystic structures within the myometrium on MRI is pathognomonic for adenomyosis. Myomas are frequent benign tumors of the myometrium that can be asymptomatic or cause menometrorrhagia, pelvic pain, and infertility. MRI allows a precise pre-therapeutic cartography of myomas. Their location should be described using the FIGO classification. Several variants of myomas exist and can be approached by MRI. Leiomyosarcoma is the most important differential diagnosis as its prognosis is poor and its treatment should be performed in reference centers to avoid local dissemination. Differentiating benign myoma from leiomyosarcoma is challenging. An MRI-based algorithm can be followed to characterize myometrial masses. Typically, leiomyosarcomas are ill defined, heterogeneous, and necrotic-hemorrhagic with tissular portions in intermediate T2 signal and significant diffusion restriction. When a myometrial mass is not typical for myoma or leiomyosarcoma, a biopsy can be offered when accessible in specialized centers after following multidisciplinary tumor board discussion.