Bowen's disease, or squamous cell carcinoma in situ (SCCIS) of the skin, is a malignant neoplasm restricted to the epidermis, without evidence of dermal invasion. It usually develops in sun-exposed areas of skin, but other sites can also be affected. However, Bowen's disease of the nipple is extremely rare. We present a case of Bowen's disease of the nipple in a middle-aged woman who presented with a scaly lesion on the nipple for several months. She also had tongue cancer and received surgical excision following concurrent chemoradiotherapy 10 years earlier. The patient was treated with a simple mastectomy and sentinel lymph node biopsy. To the best of our knowledge, this is the first reported case in the literature of Bowen's disease of the nipple in a woman with tongue cancer. Bowen's disease of the nipple clinically resembles Paget's disease. Therefore, even when diagnostic imaging cannot rule out breast cancer, squamous cell carcinoma should be included in differential diagnosis of scaly lesion of the nipple.