Companion animals are living increasingly longer lives and roughly 30% of the animal population is now considered to be geriatric. Attention to the unique physiology, presence of concurrent disease and particular requirements of individuals within the 'senior' age group will contribute to the provision of safe, effective anesthesia and analgesia. A decrease in basal resting metabolic rate with age results in a reduction in the production of body heat. Consequently, geriatric individuals are less able to maintain core body temperature. This is particularly important in anesthetized animals placed in cold environments during anesthesia or recovery. As with patients of any age, anesthetic drugs should be titrated to effect and patients monitored closely during anesthesia. Inhaled anesthetics allow rapid titration of anesthetic depth. This is very useful for geriatric patients where the response to a given dose can vary with age, pre-existing disease, and physiologic state of the patient.