The incidence of cardiopulmonary disease increases with age. Degenerative valvular disease, chronic obstructive pulmonary disease, and arrhythmias are common in the geriatric dog. Chronic bronchial disease, pulmonary neoplasia, and arrhythmias occur in the geriatric cat. Systemic diseases in both species often show cardiopulmonary manifestations. Medical management to treat the underlying disease and to control clinical signs is complicated by altered absorption, metabolism, and elimination of drugs.