Besides ER, Law & Order, daytime soap operas, or sketch comedy shows are there any other scripted TV shows that experienced an entire main cast change? Not necessarily all at once, and excepting pilots.

CSI rotated out most of its cast. George Eads was the only cast member who stayed with the series throughout its run. And then he didn't even appear in the finale.

Power Rangers would replace a couple characters every season. I think it eventually got to the point (up until Power Rangers: Lost Galaxy) where the whole cast would change every year.

Speaking of Law & Order, I think Mariska Hargitay is the only person left from Season 1 of L&O: SVU, but Ice-T has been there since Season 2.

Kids Incorporated

The spinoff of Ghostwriter

The closest one's I can think of are:

Grey's Anatomy: from the season 1 cast, only Ellen Pompeo, Chandra Wilson, James Pickens Jr and Justin Chambers remain. Since season one, the series has seen dozens of cast changes, including the exits of original cast members Katherine Heigl, TR Knight, Patrick Dempsey, Sandra Oh and Isaiah Washington.

Beverly Hills, 90210: By the time the series got to season 10 (its final season), the only original cast members remaining who had stayed the entire time were Brian Austin Green, Tori Spelling, Ian Ziering, and Jennie Garth. Most of the original cast had left at that point (with only Luke Perry returning for an extended period of time after leaving the series). Cast members who had exited include Shannen Doherty, Jason Priestley, Tiffani Thiessen, Gabrielle Carteris, Kathleen Roberston and numerous others.


Melrose Place: By the time the series ended its final season, the only original cast member remaining was Thomas Calabro. Though Josie Bissett was on the final season, she had left the series for a period of time. Keep in mind that Heather Locklear, the most famous cast member was not an original cast member joining the series midway through the first season as a guest star and being promoted to lead star before season two began. The series had gone through several rounds of big cast changes in its run.

Anything But Love: This ABC sitcom was notorious for changing its cast throughout its run. It aired for four seasons and only Jamie Lee Curtis, Richard Lewis and Richard Frank remained throughout the entire run. Every season saw multiple cast changes, and changes it the series setting.

Ellen: After season one, ABC not only changed the title of this show from "These Friends of Mine", to avoid confusion with the wildly popular NBC series "Friends" which debuted around the same time as "Ellen"; but they also fired most of the supporting cast. Maggie Wheeler and Holly Fulger were fired as Ellen's friends, there characters never mentioned again, and Joley Fisher was brought in. Several other changes occured in future seasons, most notably firing Ayre Gross and adding Jeremy Piven (though these did not occur at the same time).

The Doris Day Show started out as the story of a widow with two kids moving back to her father's ranch after her husband died. It ended up with a woman who never once mentioned she had children, working as a writer/editor at a sophisticated magazine. Doris Day herself was the only member of the cast to last the entire run of the show.

Ellen: After season one, ABC not only changed the title of this show from "These Friends of Mine", to avoid confusion with the wildly popular NBC series "Friends" which debuted around the same time as "Ellen"; but they also fired most of the supporting cast. Maggie Wheeler and Holly Fulger were fired as Ellen's friends, there characters never mentioned again, and Joley Fisher was brought in. Several other changes occured in future seasons, most notably firing Ayre Gross and adding Jeremy Piven (though these did not occur at the same time).

This is the one that came to my mind. Only Ellen remained. The removal of the original cast on that show was so bizarre, and I don't think it's ever been fully explained.

The Lucy Show was another one where nearly the entire cast was removed. Mr Barnsdahl; Lucy's son and daughter, Jerry and Chris; and Vivian Vance and her TV son Sherman all went away. Only Lucy was left.

Of course, the leads on both these shows stayed, so maybe these examples don't count. Still, they are pretty stunning examples of casting turnover.