Welfarism is the view that morality is centrally concerned with the welfare or well-being of individuals. The division between welfarist and non-welfarist approaches underlies many important disagreements in ethics, but welfarism is neither consistently defined nor well understood. I survey the philosophical work on welfarism, and I offer a suggestion about how the view can be characterized and how it can be embedded in various kinds of moral theory. I also identify welfarism's major rivals, and its major attractions and weaknesses.