Caveolin-1 (cav1) is a 22kDa membrane protein essential to the formation of small invaginations in the plasma membrane, called caveolae. The cav1 gene is expressed primarily in adherent cells such as endothelial and smooth muscle cells and fibroblasts. Caveolae contain a variety of signaling receptors and cav1 notably down-regulates transforming growth factor (TGF)- signal transduction. In pulmonary pathologies such as interstitial fibrosis or emphysema, altered mechanical properties of the lungs are often associated with abnormal extracellular matrix (ECM) deposition. In this study, we examined the physiological functions and the deposition of ECM in cav1^-/- mice at various ages (1 to 12 months). Cav1^-/- mice lack caveolae and by 3 months of age have significantly reduced lung compliance and increased elastance and airway resistance. Pulmonary extravasation of fluid, as part of the cav1^-/- mouse phenotype, probably contributed to the alteration of compliance, which was compounded by a progressive increase in deposition of collagen fibrils in airways and parenchyma. We also found that the increased elastance was caused by abundant elastic fiber deposition primarily around airways in cav1^-/- mice at least 3 months old. These observed changes in the ECM composition probably also contributes to the increased airway resistance. The higher deposition of collagen and elastic fibers was associated with increased tropoelastin and col12 and col31 gene expression in lung tissues, which correlated tightly with increased TGF-/Smad signal transduction. Our study illustrates that perturbation of cav1 function may contribute to several pulmonary pathologies as the result of the important role played by cav1, as part of the TGF- signaling pathway, in the regulation of the pulmonary ECM.