Pulmonary emphysema is characterized by the irreversible loss of pulmonary alveoli. Despite recent advances in the understanding this disease, its treatment remains palliative. In this review, we will successively review the data suggesting (1) that alveolar regeneration systems are functional in the mammalian lung and have the potential to regrow lost alveoli, (2) that cigarette smoke, the main etiologic factor of emphysema, inhibits those systems under experimental conditions, and (3) that alveolar regeneration systems are dysfunctional in the human emphysematous lung and may be a target for therapeutic intervention in this disease. Special emphasis will be put on the role of alveolar fibroblasts in those processes.