The dissociative anesthetic ketamine has been subject to growing abuse worldwide, particularly in adolescents. This project compared the effects of ketamine in conditioned place preference and intravenous self-administration in adolescent (PND 28-50) and adult (>PND70) Sprague-Dawley rats. Cocaine served as a positive control. In CPP, adolescents demonstrated preferences for ketamine, while adults developed an aversion. In the self-administration procedure, adults acquired the behavior more rapidly, but there was no difference in the percentage of subjects reaching acquisition nor in responding under a progressive ratio schedule for either drug. The CPP results suggest that adolescents have a greater sensitivity to the rewarding and tolerance to the aversive effects of ketamine. The divergent results for ketamine in the adults may reflect differences in the two procedures. However, because cocaine produced only hedonic effects in both age groups, it also suggests unique characteristics of ketamine and differences in its effects based on age.