Need to protect the environment with emphasis on sustainable development is now an established common goal for the community of nations.The interdependence of the fragile ecosystem & the economic goals of a community are a scientifically established fact. The United Nations being the global platform for exchanging ideas&sharing mutual commitments among the member states, has played a key role in this area. Starting from the Stockholm Conference on Human Environment, 1972,The UN Conference on Environment and Development (UNCED) at Rio1992,World Summit on Sustainable Development (WSSD) Johannesburg, 2002, UN Conference Rio 2012, till framing ‘The Agenda 2030 for the Sustainable Development’ in 2015,the UN has been instrumental in the development of this aspect of the International Environmental Law. Various international conventions were signed as a tangible outcome of these conferences. These bilateral or multilateral agreements are now part of the customary international law.The present paper aims to take a review of the background, agendas & outcomes of these conferences. It also tries to throw light on the similarities, ambiguities & conceptual developments that were seen at these global gatherings. It also brings out the role played by various agencies of the UN such as UNEP & ICJ to promote sustainable development.

KEYWORDS: Sustainable Development, Stockholm Conference, Rio Conference 1992, Agenda 2030.