Early onset ataxia telangiectasia (A-T) is a neurodegenerative DNA-instability disorder, which presents early in childhood. Hallmarks of A-T are progressive ataxia and a dramatic increased risk of developing malignancies (25%), especially of hematological origin. In children these malignancies mainly concern aggressive Non-Hodgkin lymphoma, acute leukemias and Hodgkin lymphoma. Of the acute leukemias, T-cell lymphoblastic leukemia (T-ALL) is by far the most common. Since patients with A-T experience increased toxicity to radio- and chemotherapeutic treatment, the optimal treatment strategy of acute leukemia remains subject of debate. Review of literature of treatment of T-ALL in patients with A-T (n = 18) showed that many patients are not diagnosed with A-T at time of presentation of T-ALL. This implicates that physicians must be aware of symptoms of A-T in young patients presenting with T-ALL. Complete remission rates are high following upfront modified as well as unmodified treatment strategies. Treatment of ALL in children with A-T is feasible and should be performed. Definitive treatment strategy must be determined by shared decision making with patient, caretakers and medical team. Future prospective studies are needed to elucidate optimal treatment strategy.