Myeloid Sarcoma is a rare tumor composed of myeloblasts occurring at an extramedullary site like bones, or various soft tissues. Myeloid sarcoma may involve the gastrointestinal tract very rarely either solitarily, or occurring simultaneously with acute myeloid leukemia. Its diagnosis is challenging and needs biopsy and immunohistochemical staining. We are describing a case of myeloid sarcoma which presented as a painful anal ulcer mimicking an atypical fissure. Its appearance resembled crohn's disease on sigmoidoscopy. A biopsy of the ulcer along with histochemical staining led to the diagnosis of myeloid sarcoma. Our case demonstrates the need for aggressive evaluation of any common gastrointestinal complaint with an atypical presentation.