We report a case of adenomyoma of the small intestine arising in a Meckel diverticulum. The patient was a 22-month-old boy who presented with signs and symptoms of intussusception. At surgery, a Meckel diverticulum was found and removed. On histologic examination, a tumor consisting of dilated cystic glands and smooth muscle bundles was identified. A diagnosis of adenomyoma arising in a Meckel diverticulum was made. A review of the literature showed that only six other pediatric cases of adenomyoma of the small intestine have been reported. The presence of an adenomyoma in a young patient within a Meckel diverticulum favors the view that adenomyomas are a variant of pancreatic heterotopia.