Low expression of T-cell receptor-CD3 (TCR-CD3) complex, a rare cause of combined immunodeficiency, has only recently begun to be recognized. Here we report a four-year-old boy who has defective TCR-CD3 complex expression presenting with recurrent chest infections and pulmonary symptoms implying bronchial asthma. In our opinion, this entity should be borne in mind as the possible underlying defect in children with combined immunodeficiency having signs and symptoms of humoral immunodeficiency.