Patients with a primary immunodeficiency syndrome have an increased risk of developing a malignancy. Lymphoreticular malignancies are the most common malignancies in these patients. Patients with ataxia telangiectasia (AT) also appear to be at a high risk for the development of nonlymphoid tumors--in particular, carcinomas of the gastrointestinal tract and central nervous system tumors. We describe a child with an immunodeficiency and slight neurological manifestations. During childhood she developed three consecutive primary malignancies.