Bronchiectasisisdefined as a permanent and irreversibleincrease in bronchial caliber, affecting at least two lobes of the lung. It is a frequentpathology in developing countries, but remainsunderestimated.There are manyetiologies, includingprimary immune deficiency, whichisconsidered the second mostcommon cause of bronchiectasis in childrenaftercysticfibrosis. We report the case of a 21-year-old patient admitted for the management of an infectious exacerbation of diffuse bronchiectasissecondary to a primary immune deficiency of the ataxia-telangiectasia type. Wewill cite somestudies in the literaturewith a discussion on the main mechanism of bronchiectasisassociatedwithataxia-telangiectasia and itsprevalencecompared to otheretiologies.