The transfer of protective genes to the alveolar epithelium can attenuate lung injury if accomplished before its onset. The pathobiology of acute lung injury (ALI) includes formidable hurdles to gene transfer, including alveoli filled with fluid, inflammatory cells, and cytokines, all of which may impair gene transfer after the onset of injury. We tested the hypothesis that adenovectors could efficiently transduce injured alveoli by exposing adult, male Sprague-Dawley rats to 100% oxygen for 48 or 60 h before endotracheal instillation of either 1 x 10(9) or 4 x 10(9) plaque-forming units of an adenovirus that expresses an Escherichia coli lac Z gene (adbeta-gal) in a surfactant-based vehicle (Survanta). X-gal staining 72 h postinfection revealed transgene expression in all segments of room air control and hyperoxic lungs infected with either dose of adbeta-gal. Net transgene expression in hyperoxic lungs was not different from room air controls despite the presence of pulmonary edema and severe histologic injury. These findings show that adenovectors can efficiently transduce the alveoli of acutely injured, edematous lungs. The data indicate that the pathophysiologic processes of ALI do not impair adenoviral-mediated alveolar gene transfer and provide support for the development of gene therapies for ALI.