The Associated Press is calling the Mississippi Democratic Primary for Sen. Barack Obama.
Obama began the night with 1,579 delegates, to 1,473 for Sen. Hillary Clinton. It takes 2,025 to win the nomination.
Arizona Sen. John McCain won Mississippi's Republican primary a week after he secured his party's nomination during primaries in Texas, Ohio and other states.
The Associated Press made its projection based on surveys of voters as they left the polls.
Election officials in several counties reported low to moderate turnout, while the state Democratic Party said it received reports of strong turnout in some precincts as the state held the nation's only presidential primary of the day.
The state also has seven Democratic superdelegates who decide on their own which candidate to support. Three are committed to Obama, three are uncommitted and one will be chosen at the state party convention in June.
State Democratic Party chairman Wayne Dowdy is one of the uncommitted superdelegates. He told The AP he will remain uncommitted, possibly until the August 25-28 national convention.