Ataxia-telangiectasia is an autosomal recessive disease characterized by progressive cerebellar ataxia, oculocutaneous telangiectasia, immunodeficiency, high incidence of cancer, and increased sensitivity to ionizing radiation. The authors report a case of dysgerminoma in a child with high alpha-fetoprotein, CA125 and beta-human chorionic gonadotropin, who has been followed-up for ataxia-telangiectasia for 2 years.