Numerous studies suggest that economics students act in a more self-interested manner, on average, than other students. According to much of the literature on the topic, this is due, at least in part, to the economics training itself with its emphasis on self-interest. The current study turns this question on its head and asks whether teaching ethics in economics classes can produce more pro-social behavior. A classroom experiment examines possible effects of two types of ethics instruction, moral duty and enlightened self-interest, on two economically important types of pro-social behavior, viz., generosity and cooperation. The main findings are that generosity is higher following instruction that stresses moral duty, that cooperation is not significantly affected but is positively correlated with generosity, and that business and economics majors are less cooperative than other majors.