On a show that aired Monday, Winfrey gave more than 300 audience members $1,000 debit cards sponsored by the Bank of America to donate to a charitable cause.
Winfrey called the show her "favorite giveaway ever."
"I can honestly say that every gift I've ever given has brought at least as much happiness to me as it has to the person I've given it to," the 52-year-old talk-show host said. "That's the feeling I want to pass on to you."
People can give the entire sum to one person — relatives aren't eligible — or they can split it among charitable causes. Audience members also received a DVD recorder to tape their stories for a future show.
"You're going to open your hearts, you're going to be really creative, and you're going to spend it all at once on one stranger or spend a dollar on every person," Winfrey said. "Imagine the love and kindness you can spread with $1,000."