The abdominoperineal pull-through procedure was the standard management of imperforate anus before the introduction of posterior sagittal anorectoplasty. Adenocarcinoma arising from the pulled-through anorectum is extremely rare and has been documented in only three reports. We describe a 21-year-old man with history of imperforate anus that was treated by pullthrough procedure at the age of one year, who later developed adenocarcinoma over the formed anorectum. Despite radical surgery and adjuvant chemoradiation therapy, the patient died of his disease six months after surgery. Review of his family pedigree showed no familial history of colorectal cancer or associated genetic disease. Chronic inflammation of the mucocutaneous junction seems to be the predisposing factor for malignant generation. We suggest that patients with an imperforate anus undergoing the pull-through operation should receive annual follow-up with careful digital rectal examination. If a suspicious lesion appears, incisional biopsy should be made to detect the inflammatory process and early malignant changes in the pulled-through anorectum to allow for appropriate treatment in the early stage.