Wegener's granulomatosis is a multisystem disorder characterized by necrotizing granulomatous inflammation and vasculitis of small vessels and can affect any organ system. The most common sites of involvement are upper and lower respiratory tracts, and kidneys. Breast involvement is unusual and very rare. We report a case of breast Wegener's granulomatosis in a 32-year-old woman who presented with pulmonary lesions and palpable masses in the left breast. Mammography showed multiple, sharply delineated nodules without microcalcifications. Ultrasonography revealed multiple hypoechoic solid lesions, some of them with anechoic areas of necrosis. Computed tomography showed multiple nodules. Histopathology of excision biopsy specimens of breast lesions revealed necrotizing granulomatous material consistent with Wegener's granulomatosis. Twenty reports of breast involvement in this rare disease were found in the literature; however, the respective ultrasonographic and computed tomography findings have not hitherto been described.