'We want to put an end to (apartheid) and the only way to do that is for our brothers and sisters around the world and in this country to give us the money that will enable us to win the election,' Mr Mandela told a rally of about 2,500 supporters., after being honoured by President Bill Clinton.
'We have popularity. What we want is power in our country. We want to turn that popularity into political power.'
Earlier, he and the South African President, F W de Klerk, were jointly awarded the Philadelphia Liberty Medal by Mr Clinton and the mayor of Philadelphia, Edward Rendell, at an Independence Day ceremony. President de Klerk and Mr Mandela shared the dollars 100,000 (pounds 68,027) prize.
Mr Mandela and Mr de Klerk both cited American constitutional principles as the key to the search for a non-racist government to replace 350 years of white domination in South Africa.
At a church service Mr Mandela said the ANC would need dollars 43m to contest the elections set for 27 April. Much of the money would have to come from abroad.
Later the National Party and the ANC in Johannesburg argued about Mr Mandela's refusal to be photographed with Mr de Klerk in the US.
'(Mr Mandela's) behaviour is definitely no credit to our country and definitely does not credit himself or the ANC,' the National Party said in a statement yesterday, accusing the ANC leader of acting like 'a bull in a china shop'.