Adenomyoma of the small intestine is a rare tumor-like lesion composed of exocrine-type ducts and hypertrophic smooth muscle. We describe two cases of adenomyoma of the small intestine. One was an ileal adenomyoma that presented with intussusception occurring in a 7-month-old boy. The other was a jejunal adenomyoma found incidentally in a 63-year-old man with colon cancer. Histologically, the lesions composed of benign ducts and bundles of smooth muscle. The second case was detected on contrast-enhanced computed tomography scan as a small enhancing polypoid mass. We review the previous literature of adenomyoma of the small intestine.