The present study assessed the effect of petting a dog on secretory immunoglobulin A (IgA) levels. 55 college students were randomly assigned to either an experimental group or one of two control groups. Group 1 (n= 19) petted a live dog; Group 2 (n = 17) petted a stuffed dog, while Group 3 (n = 19) simply sat comfortably on a couch. Each participant was exposed to one of the three conditions for 18 min. Pre- and posttreatment saliva samples yielded a significant increase in IgA for Group 1 only. Participants were also asked to complete the Pet Attitude Scale of Templer, Salter, Dickey, Baldwin and Veleber. Scores on this scale correlated with IgA increases only for participants in Group 2 (petting a stuffed animal). Results are discussed in terms of the beneficial effects of pets on health in general, and immunity in particular.