In their justification of individual entitlements, libertarians appeal to the concept of self-ownership. This paper argues that taking into account the division of labour in society calls for a fundamental reassessment of the normative implications of self-ownership. How should the benefits from division of labour—in other words, how should the co-operative surplus—be distributed? On the assumption that the parties to the division of labour are interdependent, and that this interdependence is mutual and of the same degree, I argue for an equal distribution of the co-operative surplus. In form, my argument bears similarities to the left-libertarian position that calls for an equal distribution of natural resources. Despite its radically egalitarian implications, an equal distribution of the co-operative surplus remains a libertarian principle.