CBS has picked up fifth installments of the reality series "Big Brother" and "The Amazing Race."

Meanwhile, NBC has ordered additional episodes of its summer reality series "The Restaurant" targeted for late midseason.

The Julie Chen-hosted "Big Brother" is set to return in summer 2004, while "The Amazing Race," which won an Emmy this month for best reality/competition program, has received a 13-episode order for midseason or summer.

"I think qualitatively, both shows are absolutely at their peak," said Ghen Maynard, head of CBS' alternative programming department. "I think what we've really done well at CBS and what our whole goal has always been with shows like 'Amazing Race,' 'Big Brother' and 'Survivor' is to create long-lasting franchises that have appeal for the long term."

In addition to "Big Brother," "Amazing Race" and the CBS' flagship reality series, "Survivor," also returning are "Star Search" as well as "America's Next Top Model" on sister Viacom network UPN, which is also overseen by CBS chairman and CEO Leslie Moonves.

There are discussions going on regarding the Simon Cowell-produced series "Cupid," but there is no decision yet whether the dating show will return, Maynard said.

"Amazing Race" has already started casting for its fifth edition, which will feature two-person teams trotting the globe for a $1 million prize.

Casting on "Big Brother" is scheduled to begin in February.

After the previous three installments of "Big Brother" that Arnold Shapiro and Allison Grodner executive produced were picked up the following February, just as the show had to start casting, "to be told five days after the last telecast (of the fourth season) that we are picked up for 'Big Brother 5' was a big relief," Shapiro said. "Allison and I are truly excited that there is going to be a 'Big Brother 5,' we're truly happy to be executive producing it again, and we're eager to throw our creativity into full gear to see what we come up with next."

"Big Brother," from Shapiro/Grodner Prods. and Endemol USA, is coming off its most successful season to date, averaging 8.8 million viewers and a 3.5 rating/12 share in adults 18-49.

"We're incredibly thrilled that we got picked up again," said "Amazing Race" executive producer Bertram van Munster. "The fifth race is laid out and ready to go, and it is shaping up to be an extreme globe-trotting event."

He declined to reveal any details about the "drastic changes" he said the producers are making to keep the series fresh, but promised that the show's regular viewers "are going to be in for a big surprise."

Van Munster is executive producing "Amazing Race" with Jerry Bruckheimer and Jonathan Littman for Bruckheimer Films, Earthview and Touchstone TV.

As for "The Restaurant," it has not been decided yet if chef Rocco DiSpirito will continue to be at the center of the show from Mark Burnett, Ben Silverman and Magna Global Entertainment.

"We're either going to continue working with Rocco -- and there are incredible story lines that haven't yet been dealt with -- or we're going to launch a new 'Restaurant' with a new chef, and we might even do both," Silverman said.

The new deal firms up Burnett and Silverman's relationship with NBC.

In addition to shepherding "The Restaurant" together, Silverman separately executive produces the network's new comedy "Coupling," while Burnett is executive producing NBC's upcoming reality series "The Apprentice."

"We are very, very happy to continue our joint relationship with NBC," Burnett said.

In addition to "The Restaurant," the two producers also are working on a new reality show for NBC that will have "similar kind of storytelling in a different arena," Silverman said.

No decision has been made yet about the new project's setting, but sources indicated that a casino is among the options being considered (HR 9/9).