The sonographic features of 22 patients with histologically benign intraductal papillomas are presented, with clinical, mammographic, galactographic, and histopathologic correlation. The most common presenting feature in this series is a palpable central breast mass in an elderly woman. Sonography was abnormal in all 22 patients. The typical sonographic features include a well-defined, smooth-walled, solid, hypoechoic nodule or a lobulated, smooth-walled, cystic lesion with solid components. Dilated ducts are a common feature, often with visible solid intraluminal echoes. These findings suggest the diagnosis of an intraductal papilloma. The differential diagnosis includes fibroadenoma and phyllodes tumor (for large solid lesions) and intracystic carcinoma (for complex cystic lesions). Mammograms are frequently normal (36% of patients). When abnormal, the mammographic features are of a smooth-walled, well-defined mass or increased retroareolar opacity. Contrary to the reported literature, calcification was seen infrequently. We conclude that ultrasonography is useful in the detection and delineation of intraductal papillomas.