Based on a retrospective analysis of 32 patients with polypoid adenomyomas of the uterus, the authors have identified 3 sonographic patterns: solid (pattern 1, 8 cases), solid with cystic areas (pattern 2, 22 cases), and predominantly cystic (pattern 3, 2 cases). Sonographic features include a heterogeneously isoechoic, polypoid, or pedunculated endometrial mass, with an ill-defined margin, hemorrhagic foci, posterior shadowing, and associated adenomyosis in the myometrium. Knowledge of these sonographic appearances may facilitate the diagnosis of polypoid adenomyoma and help differentiate it from other polypoid uterine tumors.