Sweden first suggested to the United Nations Economic and Social Council
ECOSOC in 1968 the idea of having a UN conference to focus on human interactions with the environment. ECOSOC passed resolution 1346 supporting the idea. General Assembly Resolution 2398 in 1969 decided to convene a conference in 1972 and mandated a set of reports from the UN secretary-general suggesting that the conference focus on "stimulating and providing guidelines for action by national government and international organizations" facing environmental issues.
 Preparations for the conference were extensive, lasting 4 years, including 115 governments, and costing over $30,000,000.