UNIDO was established by the General Assembly in November 1966 as an autonomous organization within the UN to promote and accelerate the industrialization of developing countries and to coordinate the industrial development activities of the UN system.
The first General Conference of UNIDO was held in Vienna in 1971. The second General Conference, held in Lima in 1975, proposed the conversion of UNIDO into a specialized agency "in order to increase its ability to render assistance to developing countries in the most efficient ways." The conference also adopted the Lima Declaration and Plan of Action, which called for developing countries to reach the target of 25% of world industrial output by the year 2000.
In 1979, a conference of plenipotentiaries, meeting in Vienna, adopted a constitution for UNIDO, to become effective when at least 80 states had ratified it. This was achieved on 21 June 1985, and UNIDO's conversion into a specialized agency became effective on 1 January 1986.