This chapter discusses the efforts of the United Nations in the promotion of prisoners' rights and humane prison conditions. It begins by reviewing the history of the United Nations' work in this field and then discusses the following: the legal nomenclature and authority of the various human rights and prisoners' rights instruments; recent concerns of the international community; the challenges to the implementation of prison standards; and the structural changes in the United Nations criminal justice programme. The promotion of norms and standards of prisoners' rights and of humane prison conditions has to be considered in the context of the promotion of human rights, generally by the United Nations. The concept of human rights is not a new idea, as the Magna Carta, French Declaration of the Rights of Man and the United States Constitution would suggest. The chapter offers some concluding thoughts on the future work of the United Nations in this arena.