Donors from around the world have pledged $4.3bn for a programme that aims to vaccinate 250 million of the world's poorest children against lifethreatening diseases.
The pledges surpassed the $3.7bn target set by the Global Alliance for Vaccines and Immunisation (GAVI), which says it could prevent more than 4 million premature deaths by 2015.
"We have exceeded the figure that we set ourselves and we have received firm pledges for a sum of $4.3bn," Andrew Mitchell, Britain's International Development Secretary announced at the end of the conference in London on Wednesday.
Britain and Bill Gates, the Microsoft chairman jointly committed $2.3bn to help vaccinate more than 80 million children in impoverished countries.
David Cameron, Britain's prime minister, said the $1.3bn donated by his country would help save 1.4 million lives over the next five years.