Prostate cancer is the second most common cancer in men in the world. The presentation of this cancer may range from microscopic to metastatic forms. Patients with prostate cancer may experience metastasis to the gastrointestinal system. Here, we present a case of prostate cancer metastasizing to the third portion of duodenum, a very uncommon site of metastasis. To the best of authors' knowledge, this is the first case report in the literature.