Two episodes of each show will air back-to-back beginning Sept. 10 with "Rachael Ray" from 9-11 a.m. and "Nate Berkus" from 11 a.m.-1 p.m.
OWN will also air reruns from the first five seasons of "Rachael Ray" and the first two series of "Nate Berkus."
"Rachael and Nate are a natural fit for OWN's expanding daytime programming lineup," Erik Logan, the network's president, said in a statement. "It will be great to have Rachael's energy and Nate's upbeat presence on our air."
Both television personalities got their start with Oprah.
Ray, a New York native, signed a deal in 2005 with Winfrey to host a day-time cooking show, fueling buzz of the launch with appearances on the Oprah Winfrey show.
Berkus started as host of the short-lived reality show "Oprah's Big Give."