Animal-assisted activity is the use of trained animals for the therapeutic, motivational, or educational benefit of patients. Subjects of this study were 218 patients hospitalized on the mental health unit of a community hospital with an existing, complementary animal-assisted activity program. Half of the patients participated in a 1-hour session of animal-assisted activity. The other half, who served as a comparison group, participated in a 1-hour stress management program. It was hypothesized that an animal-assisted activity program would improve ratings of depression, anxiety, and pain and the associated physiological measures of stress and discomfort. Self-report ratings of depression, anxiety, and pain were collected before and after treatment sessions, and blood pressure, pulse, and salivary cortisol were measured. There were significant decreases in depression (P < .0001), anxiety (P < .0001), pain (P < .0001), and pulse (P < .04) after animal-assisted activity program, comparable to those in the more traditional stress management group.