Purpose. To report a patient with primary squamous carcinoma of the rectum. Case report. A 40-year-old woman with hematochezia and change in bower habits was studied. The main laboratory finding was a mild anemia. A barium enema and a proctoscopy revealed a rectal neoplasm at eight cm from the anal verge. A transendoscopic biopsy demonstrated an squamous rectal carcinoma. A transrectal ultrasound and CT scan of the abdomen revealed a big rectal mass with transmural affection and possible involvement of the lymph nodes. The carcinoembriogenic antigen (CEA) was high (32 ng/mL). The patient underwent radiotherapy with 46 Gy, and 5-fluorouracil as radiosensitizer. Three months later, a new CT scan showed significant reduction of the size of the mass, and the patient underwent a very low anterior resection with double-stapled anastomosis. The analysis of the specimen showed a squamous carcinoma of the mid-rectum, invading through the wall without lymph node affection and with proximal, distal, and radial margins free of tumor. The CEA returned to normal after surgery (1.3 ng/mL). The patients is alive and without evidence of disease 18 months after the operation. Conclusion. Primary squamous carcinoma of the rectum is a rare disease, and surgery seems to be a good option of treatment, with the possibility of sphincter preservation depending upon the location of the tumor.