Bilateral breast carcinoma is reported to occur in 5-10% of all patients with breast cancer. Paget disease of the breast represents 1-3% of all breast malignancies [Ashikari R, Park K, Huvos AG, Urban JA. Paget's disease of the breast. Cancer 1970;26:680-5; Marshall JK, Griffith KA, Haffty BG, Solin LJ, Vicini FA, McCormick B, et al. Conservative management of Paget disease of the breast with radiotherapy. Cancer 2003;97:2142-9]. However, synchronous bilateral Paget disease of the nipple is extremely rare. We report synchronous bilateral Paget disease with infiltrative ductal carcinoma in a 74-year-old man who underwent bilateral mastectomy.