The wife of former US president Bill Clinton, Hillary Rodham Clinton, on Saturday launched her bid to become president in 2008.
"I'm in. And I'm in to win," Clinton said on her website.
Clinton, who is a senator from New York for the Democratic Party, said she was forming an exploratory committee to consider running for president, the first step towards the White House.
Clinton's announcement ended months of speculation. She now joins former vice-presidential candidate John Edwards and Illinois Senator Barack Obama in the race to win the Democratic nomination to run for president.