Recognizing the show's value, especially in its ultra-competitive 9 p.m. Thursday time slot, CBS during the summer quietly doubled the salaries of the show's two stars, William Petersen and Marg Helgenberger, and hiked pay for other key cast members as well, sources said.

Petersen, who plays quirky investigator Gil Grissom, last season made about $100,000 per episode (all figures U.S.); he now earns $225,000 to $250,000 per episode, including a producer's fee and advances against his profit participation, the sources said.

Helgenberger, who plays Catherine Willows, does not have a back-end deal or earn a producer's fee, according to sources, but her salary doubled this season to $150,000 per episode.

The forensic-science drama has become one of the biggest hits on television. Even summer repeats of CSI drew top ratings for the network.

Other cast members, including Gary Dourdan and George Eads, are believed to have received substantial raises as well.

Even after the raises, the CSI salaries do not approach those for some other popular series. The six principal cast members of NBC's Friends each earn $1 million per episode. Frasier star Kelsey Grammer reportedly makes more than $1.6 million per episode.

However, both of those shows have been on the air far longer than CSI. Moreover, hit sitcoms usually generate far more profits through syndication than hit dramas do.

Even so, the new paychecks for Petersen and Helgenberger make them among the best-paid actors on TV.

In the first season of CSI, Petersen earned $65,000 per episode, plus a $10,000-per-episode producer's fee. Helgenberger made $50,000 per episode.

By the end of the first season, when the show's ratings began to take off, CBS agreed to bump Petersen's salary. And as a token of appreciation, CBS in the spring sent each of the principal cast members a big-screen, high-definition plasma television. Each TV set is worth at least $20,000.