Do we humans ever, in any degree, care about others for their sakes and not simply for our own? Psychology has long assumed that everything humans do, no matter how nice and noble, is motivated by self-interest. However, research over the past three decades suggests that this assumption is wrong. This research has focused on the empathy—altruism hypothesis, which claims that empathic concern—an other-oriented emotional response elicited by and congruent with the perceived welfare of a person in need—produces altruistic motivation—motivation with the ultimate goal of increasing another's welfare. Results of the over 30 experiments designed to test this hypothesis against various egoistic alternatives have proved remarkably supportive, leading to the tentative conclusion that feeling empathic concern for a person in need does indeed evoke altruistic motivation to see that need relieved. Sources of altruistic motivation other than empathy also have been proposed, but as yet, there is not compelling research evidence to support these proposals. Two additional forms of prosocial motivation have also been proposed: collectivism and principlism. Collectivism—motivation with the ultimate goal of benefiting some group or collective as a whole—has been claimed to result from group identity. Principlism—motivation with the ultimate goal of upholding some moral principle—has long been advocated by religious teachers and moral philosophers. Whether either is a separate form of motivation, independent of and irreducible to egoism, is not yet clear. Research done to test for the existence of empathy-induced altruism may serve as a useful model for future research testing for the existence of collectivism and principlism. Theoretical and practical implications of the empathy-altruism hypothesis are briefly considered.