The Human Rights Council’s Universal Periodic Review (UPR) provides a unique insight into states’ perceptions of international human rights law. States issue recommendations to each other on fulfilling human rights obligations and commitments. The Council’s Resolution 5/1 sets out that the bases of the reviews are the UN Charter, the Universal Declaration of Human Rights, human rights instruments to which the state is party, voluntary pledges and commitments and previously accepted UPR recommendations. The reviews also ‘take into account’ relevant international humanitarian law. Analysing the rationales for adopting these bases of review and the actual use of these bases, we demonstrate how broadly states understand the term ‘human rights’ and states’ preferences for certain sources of human rights law. Our empirical analysis of the 57,685 recommendations made during the first two UPR cycles demonstrates that, where states refer to international legal materials they have not limited themselves to the bases of review in Resolution 5/1. Instead, they have interpreted the types of instruments and the notion of ‘human rights’ expansively. Regional human rights instruments have largely been ignored. States have rejected traditional distinctions between ‘hard’ and ‘soft’ law and recognised a body of generalized, non-specific international human rights law.