Theories abound for why individuals give to charity. We conduct a field experiment with donors to a Yale University service club to test the impact of a promise of public recognition on giving. Some may claim that they respond to an offer of public recognition not to improve their social standing, but rather to motivate others to give. To tease apart these two theories, we conduct a laboratory experiment with undergraduates, and found no evidence to support the alternative, altruistic motivation. We conclude that charitable gifts increase in response to the promise of public recognition primarily because of individuals' desire to improve their social image.