This report describes a patient with radiation-induced rectal cancer with an unusual history. A 51-year-old man was admitted in 2000 because of ichorrhea of the skin on the left loin. The patient had received irradiation for a suspicious diagnosis of a malignant tumor in the pelvic cavity in 1975. A subcutaneous abscess in the right loin appeared in 1989, and rectocutaneous fistula was noted in 1992. Moreover, radiation-induced rectal cancer developed in 2000. Plain computed tomography and magnetic resonance imaging of the pelvis demonstrated a presacral mass and tumor in the rectum. Finally, we diagnosed the presacral mass to be an abscess attached to the center of the rectal cancer. The rectum was resected by Miles' operation and a colostomy of the sigmoid colon was also performed. Many cases of radiation-induced rectal cancer have been reported. However, this is a rare case of radiation-induced rectal cancer originating from a presacral abscess and rectocutaneous fistula.