Ataxia-telangiectasia (A-T) is a multisystem disease caused by a genetic defect located on the long arm of chromosome 11 (11p22-23). The gene defect results in the loss of A-T-mutated protein, subsequently leading to unrepaired DNA fractures and defects in the signal transduction pathway. As a result, characteristic findings arise, including recurrent sinopulmonary infections, hypersensitivity against ionized radiation with the tendency to develop cancer related to progressive cerebellar ataxia, pathognomonic oculocutaneous telangiectasias, varying degrees of humoral and cellular immunodeficiency, and infertility. This case report presents a 3-year-old male patient with A-T who developed hemophagocytic syndrome. To the best of our knowledge, no such case has been previously reported.