Debates among Liberals on social justice have played a major role in current discussion on basic income (or universal benefit). In this paper, the notion is considered on the basis of the “economics of liberal egalitarianism”, for which the anchor point is to be found in Rawls’philosophical works. Although he certainly does not support basic income, he still provides an appropriate general framework to consider it, in particular because of the hierarchy of his principles of justice (I). At the third level of this hierarchy, the interpretation of the “difference principle” appeared controversial when applied to the case of the “Malibu surfers”, an illustration thanks to which Van Parijs was able to defend the unconditional nature of basic income (II). There remains the transition from the philosophy to the economics of basic income, which allows considering it as a precise alternative of negative income tax. At this stage, a rereading of Friedman’s intuition on this topic results in seeing basic income as a “universal tax credit” (3). We conclude with some prospective remarks on a possible implementation of this conception of basic income in the case of liberal democracies and of France as well (4).