Turcot's syndrome, the association of brain tumor (usually glioblastoma, medullo-blastoma, or astrocytoma) and colonic polyps, is a very rare condition of which about 20 cases have been reported. It has been described only once previously with cancer in a third organ system. In this paper, we report a child affected with colonic polyposis and astrocytoma (i.e., Turcot's syndrome) associated with intestinal non-Hodgkin's lymphoma.