Apoptosis is a critical mechanism controlling cellularity in various tissues. It is so far unknown whether apoptosis plays a critical role in the pathogenesis and development of chronic obstructive pulmonary disease (COPD). However, recent evidence suggests that apoptosis may occur in vascular endothelial cells and/or alveolar epithelial cells in COPD lungs, thereby potentially contributing to lung tissue destruction seen in COPD. Apoptosis may also influence cellular infiltrates into the lung, another pathologic feature of COPD, because the survival of inflammatory cells such as neutrophils, lymphocytes, and macrophages are critically determined by the mechanism of apoptosis.