Rectal leiomyosarcomas are rare tumors originating from smooth muscle cells. Differential diagnosis includes gastrointestinal  stromal tumors (GIST), leiomyomas or schwannomas, and the differentiation of these tumors is usually made through immunohistochemistry. Due to its rarity, the standard treatment has not been defined. The purpose of this study was to present a rare case report of rectal leiomyosarcoma in a 55 year old  male  mimicking as a pararectal GIST and successfully managed with abdominoperinealresection.Patient was discharged without any complications and is disease free 4 years after surgery.