The First source of funding for UNEP was provided for in the UN General Assembly resolution 2997 (XXV11) in 1972.

When the United Nations Environment Programme, was established the Assembly decided "That the costs of servicing the Governing Council and providing the small secretariat shall be borne by the regular budget of the United Nations..." In 1973, UNEP received $1.75 million from the regular budget, i.e 21.1% of its total financial resources that year. The corresponding figures for 1981 were US$5.3 million or 12.8%, for 1991 US$6.16 million or 6.8% and in 2002 US$4.5 million or 3.6%. In 2004-2005, UNEP received US$10.5million from the UN regualr budget. This was about 17% higher than in the previous biennium (US$8.965m).

The regular budget provides core support to UNEP, and is utilized for policy-making, executive direction and management, development of programme of work and programme support. In 2004-2005, US$ 7.9million was allocated to and directly administered by UNEP headquarters and the balance was allocated to UNEP offices in New York and Geneva and to the United Nations Scientific Committee on the Effects of Atomic Radiation(UNSCEAR) in Vienna.