A case of intestinal pseudoobstruction occurring 30 yr after radiation therapy is described. Mechanical causes of obstruction were excluded by laparotomy. Histology of full-thickness sections of the small bowel revealed vascular ectasia and sclerosis, serosal fibrosis, neuronal proliferation within the submucosa, and degeneration of the muscle fibers of the circular layer of the muscularis propria. On the basis of the clinical and histologic findings we conclude that, in this patient, intestinal pseudoobstruction was due to muscular and neuronal injury from abdominal irradiation.