The popular talk show host and media mogul plans to visit Iowa on Saturday, Dec. 8, with stops in Des Moines and Cedar Rapids. The following day, she'll travel to Columbia, South Carolina. Later that day, she'll visit New Hampshire, but a location had not been announced Monday morning.
This is not the first time Oprah has lent her star power to the Illinois senator.
In September, she rolled out the red carpet for Obama at a gala fundraiser in California that brought in about $3 million (EUR2.03 million) for his campaign.
Winfrey is a well-known fan of Obama, calling him "my favorite guy" and "my choice" on CNN's "Larry King Live" last year before he announced he would seek the presidency.
In a news release announcing the events, Obama's campaign said tickets to the Iowa events will be given first to precinct captains, then campaign volunteers, then to supporters and undecided caucus-goers.
It said volunteers can be guaranteed a ticket by completing a four-hour volunteer shift or attending local caucus training before the event.