The Oprah Winfrey Show, an iconic broadcast that grew from a local Chicago talk show into the foundation of a multibillion dollar media empire, will end its run in 2011 after 25 seasons on the air, Winfrey's production company said last night.

Winfrey plans to announce the final date for her show during a live broadcast today, Harpo Productions Inc. said. A Harpo spokeswoman declined to comment on Winfrey's future plans except to say that The Oprah Winfrey Show will not be transferred to cable television.

Winfrey is widely expected to start up a new talk show on OWN: The Oprah Winfrey Network, a much-delayed joint venture with Discovery Communications Inc. that is expected to debut in 2011. OWN is to replace the Discovery Health Channel and will debut in some 70 million homes.

CBS Television Distribution, which distributes The Oprah Winfrey Show to more than 200 markets blanketing the United States, held out hope that it could continue doing business with Winfrey, perhaps producing a new show out of its studios in Los Angeles.

"We have the greatest respect for Oprah and wish her nothing but the best in her future endeavors," the unit of CBS Corp. said in a statement. "We know that anything she turns her hand to will be a great success. We look forward to working with her for the next several years, and hopefully afterwards as well."

Winfrey's 24th season opened earlier this year with a bang, as she drew more than 20,000 fans to the city's Magnificent Mile on Michigan Avenue for a Chicago block party with the Black Eyed Peas.

She followed up with a series of blockbuster interviews - Mike Tyson and Evander Holyfield, exclusives with singer Whitney Houston and ESPN's Erin Andrews, and just this week, former Alaska governor, GOP vice presidential candidate and best-selling author Sarah Palin. She found time between shows to lobby the International Olympic Committee in Denmark for Chicago's failed bid to host the 2016 Olympics.

The loss of The Oprah Winfrey Show would be a blow to CBS Corp. because it earns a percentage of hefty licensing fees from TV stations that use it.