Public procurement refers to the purchasing of goods, services and works by governments and public authorities. Given the difficulty in defining a common core of social considerations applicable to the generality of public contracts, this paper aims at proposing a distinction between two categories of social objectives: on the one hand, the promotion of work standards and fundamental human rights as a hard core, and on the other hand, the promotion of inclusion and supplier diversity as a further step of the social-oriented approach. This concerns not only the mere procurement process but also the entire supply chain, leading to distinguish between the basic responsible supply chain involving the respect of internationally recognised human and labour rights, and the pro-active responsible supply chain promoting inclusion and supplier diversity. Based on this distinction, this paper analyses if basic working conditions and fundamental rights can be generally taken into account in public procurement. Implications of this assumption affect different levels of the procurement process and policy: from policy considerations to tender design, from economic efficiency matters to monitoring issues.