Signatories include South African Nobel Peace Prize Laureate Archbishop Desmond Tutu; YWCA head, Musimbi Kanyoro; the general secretary of the World Alliance of Reformed Churches, the Rev. Setri Nyomi; Lutheran World Federation leaders the Rev. Ishmael Noko and Bishop Mark Hanson, who heads the Evangelical Lutheran Church in America. More than 350 heads of men's and women's religious orders in the Roman Catholic Church have signed as well.

The G8 consists of Britain, Canada, France, Germany, Italy, Japan, Russia and the United States and the group was once referred to as the world's leading industrial nations. It will hold its next summit in Heiligendamm, Germany from June 6-9.

The letter reminds the leaders of the commitments made at the G8 Summit held in Scotland in July 2005 that later received global affirmation at the UN High Level Meeting on AIDS in June 2006. Key to the commitments is the stated goal of reaching "Universal Access to comprehensive prevention programmes, treatment, care and support by 2010."

"Without sufficient financial and leadership commitment from G8 countries," the letter states, this promise "has little meaning."

The Geneva-based Ecumenical Advocacy Alliance, which released a statement on the letter, said that currently 75 percent of people who urgently need treatment for HIV are not receiving it and that three million people died of AIDS-related illnesses in 2006. It said more than 25 million people are estimated to have died from AIDS-related illnesses since the disease was identified in the early 1980s. Around 40 million people are currently living with HIV.