In a video-link address to the closing session of a week-long international conference on AIDS, Obama and his Secretary of State Hillary Clinton said their focus was on a broad, sustainable and effective approach to the global epidemic.
Ending this pandemic won't be easy, and it won't happen overnight, said Obama, whose administration has come under attack during the conference for failing to increase global funding for the fight against AIDS.
Obama said he was facing a tough fiscal environment at home but said the United States was committed to helping AIDS health charities and aid workers build on progress.
The human immunodeficiency virus (HIV) that causes AIDS currently infects 33.4 million people globally, the majority of them in the world's poorest countries in sub-Saharan Africa.
It has killed 25 million people since the early 1980s.
Advances in AIDS medicines have effectively turned an acute killer disease into a manageable chronic condition in many wealthy countries, and some 5.2 million people who need AIDS drugs can now get them. But funding shortages in many poor countries mean that another 10 million people who have HIV and need treatment still cannot get access to medicines.
A report published at the Vienna conference by the Joint United Nations Program on HIV/AIDS (UNAIDS) found that overall support for the global AIDS effort from donor nations flattened out last year in the midst of global economic crisis.
In 2009, the Group of Eight leading wealthy nations, the European Commission and other donor governments provided $7.6 billion for AIDS relief in developing nations, compared with $7.7 billion disbursed in 2008, it said.
Obama's Global Health Initiative is a $63 billion health aid program designed to tackle various diseases and help build better health systems in poor nations.
But some AIDS activists say Obama's focus on this initiative is robbing funds from other programs such as the Global Fund to Fight AIDS, Tuberculosis and Malaria.
The head of the Global Fund -- the world's largest funder of AIDS programs -- has said he is very worried about the prospect of getting the $20 billion needed to continue the AIDS battle for the next three years.
Clinton, who also addressed the Vienna conference via video-link, said access to HIV/AIDS prevention, treatment and care should be a universal, shared responsibility.
The international AIDS conference, which is held every two years, moves to Washington in 2012.