A Vienna ball that raises money for HIV/Aids charities is set to be held for the last time in June.
Organisers say it is "increasingly difficult to find sponsors" due to progress in tackling the virus.
However, the charity One says HIV/Aids is still a crisis "especially in the developing world".
The Life Ball, which has run for 26 years, has raised more than €30m (£26m; $34m) for HIV/Aids charities in Austria and around the world.
The final event will be held on 8 June.
The event has become a major fixture on the city's calendar with up to 45,000 spectators a year. Previous attendees include Elton John, former US president Bill Clinton and musician Fergie.
Life Ball founder and organiser Gery Keszler said in a statement: "We achieved more than we ever dared hope. I am so eternally grateful. It is now time to bring this project to a fitting conclusion.
"We have achieved a lot in the fight against Aids. Aids has changed from a death sentence to being a chronic disease. The paradox of this success is that the number of allies for Aids charity projects is decreasing both at home and abroad."
Mr Keszler said that there are still "great challenges" around the world especially in Africa and funds raised from this year's ball will target areas "where the problem is still acute".
However Diversity Care Vienna, a mobile care organisation, said it was facing a financial crisis without funding from Life Ball.
The Life Ball was founded in 1993 and takes place at Vienna's City Hall. This year's theme is "United in Diversity".
Romilly Greenhill, UK Director at One told the BBC that "fantastic progress" had been made in fighting HIV but that Aids was still a global crisis.
She said: "There are 1,000 young women and girls that are going to be infected with HIV today and 1,000 tomorrow. By this time next week 7,000 women and young girls will have been infected by HIV. That is still an enormous problem.
"Aids is also the number one killer of women under 50 worldwide and that is something that we are incredibly concerned about and are urging young leaders to tackle.
"There's an organisation called the Global Fund to fight Aids, TB and Malaria. It's had fantastic success - 27 million lives have been saved since it started in 2002. But it needs to keep getting the resources required to keep up the fight and to step up the fight against HIV/Aids."