Humans have a drive to evaluate themselves by examining their abilities and outcomes in comparison to others. The present study examined the emotional and neural correlates of upward social comparison (comparison with those who have more) and downward social comparison (comparison with those who have less). Two experiments were conducted with volunteers in an interactive game of chance, in which a putative player won or lost more money than the participant. The results showed that even when participants lost money, they expressed joy and schadenfreude (gloating) if the other player had lost more money. On the other hand when they actually won money, but the other player had won more they expressed envy. This pattern was also demonstrated in a differential BOLD response in the ventral striatum. Comparing the activations between an actual gain and a relative gain indicated that even when a person loses money, merely adding information about another person's greater loss may increase ventral striatum activations to a point where these activations are similar to those of an actual gain. We suggest that the ventral striatum plays a role in mediating the emotional consequences of social comparison.