Dogs (N = 108) in an animal shelter received one of four enrichment programs: twice daily walking alone (walking) or in combination with a daily fooddispensing toy (toy), a daily session of standardized human contact (petting), or daily obedience training (obedience). We evaluated the effects of enrichment on: a) cortisol concentrations intermittently sampled across approximately days 2-10 in the shelter; b) behavior during an in-shelter mock adoption session; c) adoptability; d) behaviors in the adoptive homes; and e) frequency of retention up to 6 months post-adoption. Within enrichment groups, blood cortisol concentrations did not change from approximately day 2 to day 6 of residence in the shelter, but decreased significantly from approximately day 6 to day 10 only in dogs in the walking group. Among groups, changes in blood cortisol concentrations did not differ across sampling days. During an in-shelter mock adoption session, there were no differences among groups in attention-seeking behaviors, time sitting or lying, or time to approach the mock adopters. Dogs in the petting and obedience groups performed more ambivalent behaviors during the session on approximately days 9-10 of residence in the shelter than did dogs in the walking group. There were no differences in proportions of dogs adopted or on time to adoption among enrichment groups. However, more adopters of dogs in the toy and obedience groups selected their dogs because the dogs "did not bark" than did adopters of dogs in the walking group. At 1 month post-adoption, dogs in the obedience group displayed "hyperactive" behaviors more frequently than dogs in the walking and toy groups. Furthermore, dogs in the walking and petting groups displayed more annoying barking at 1 month post-adoption than dogs in the toy group. Seventeen percent of dogs were returned by 6 months post-adoption: four in the walking group, two in the toy group, one in the petting group, and four in the obedience group. The reasons for returning and the time to return did not vary among enrichment groups.