A 26-year-old-woman was given a diagnosis of Wegener's granulomatosis and began treatment by both prednisolone and cyclophosphamide at another institution. She was then admitted to our hospital due to progressive multiple pulmonary nodules. A diagnosis of pulmonary metastases from bladder cancer was established with radiological and histological examinations obtained by transbronchial lung biopsy (TBLB) and transurethral resection of the bladder tumor (TUR-Bt). She had already received a total dose of 120 g of cyclophosphamide, which could be related to the development of bladder cancer. On detecting multiple pulmonary nodules in patients with Wegener's granulomatosis treated with cyclophosphamide, it is necessary to consider the possibility of pulmonary metastases form urinary bladder cancer.