To clarify the magnetic resonance (MR) characteristics of primary uterine malignant lymphoma, we identified 4 patients with primary uterine lymphoma in the MR database of our institute from 1994 to 2005 and evaluated their clinical and MR findings for tumor extension, size, shape, and signal intensity, multinodular growth pattern, preservation of normal endometrium, and lymphadenopathy. In all 4 patients, tumors extended to the uterus and vagina or parametrium, and uterine tumors showed relatively homogeneous intensity on both T(1)- and T(2)-weighted MR imaging. Two patients showed multinodular tumor growth; three revealed pelvic lymphadenopathy; and none had intact endometrium or normal uterine zonal structure. Thus, large tumors with relatively homogeneous signal intensity seemed to be a specific MR finding of uterine lymphoma, and findings of multinodular growth were considered a possible characteristic suggesting the uterine involvement of malignant lymphoma.