After a long silence economists have started again to research and study economic inequality. Over the last two decades remarkable advances have been made on various issues related to economic inequalities. However a poorly debated question is why economic inequality is a problem. Indeed, economists have put forward several arguments in support of the idea that inequality is not a major problem. Such arguments span from the positive impact of inequality on economic growth, to the consideration that poverty not inequality is the problem and, finally, that we should care only about equality of opportunity. This essay provides a critical assessment of all these ideas and offers an attempt at defining the conditions under which economic inequality can be considered just or, at least, less unjust than it is today.