Barack Obama says he's won the battle to be the Democratic candidate in this year's American Election.
He told cheering crowds that he had got more support from party members than his rival Hillary Clinton.
Mr Obama made his speech on the last day of the primaries, which are a series of votes to decide who'll go on to fight for the job of president.
It's been a close battle between the Democrat candidates, and Mrs Clinton has still not admitted she's lost.
If Illinois senator Mr Obama is confirmed as the candidate by party officials, he'll be the first black candidate to be nominated by one of the big US parties.
Hillary Clinton still hasn't given up
The other side, the Republican Party, picked Arizona senator John McCain as their candidate months ago.
So it looks like he'll be fighting Mr Obama for the job of president in the election in November.