Ataxia telangiectasia is a rare genetic disease characterized by neurological manifestations, infections, and cancers. In addition to these cardinal features, different autoimmune diseases can be seen in patients with ataxia telangiectasia. Although there were reports of positive autoimmune thyroid antibodies associated with ataxia telangiectasia, to our knowledge, we report the first cases of nodular Hashimoto thyroiditis in two patients with ataxia telangiectasia in the English medical literature. These cases illustrate that despite the rarity of nodular Hashimoto thyroiditis associated with ataxia telangiectasia, physicians should be aware of this possibility. Furthermore, thyroid examination of patient with ataxia telangiectasia is recommended for early diagnosis.