TV shows that changed their theme song during its run

[K7P5V]

Samurai Jack would be my choice:

[Joker]

Scrubs used an alternate version of the theme song during season 2. It was not good. They went back to the original for every other season.

[Zero Hunter]

Babylon 5 changed its theme and opening spoken word intro after the main character left and when the "last, best hope for peace" ...failed. I think it changed every season.

The spoken word part did. The first season was Sinclair narrating. Season 2 was Sheridan. Season 3 was Ivanova. Season 4 was the whole cast did it. Season 5 was spoken clips from the first 4 seasons.

[caj]

The Wonder Years

The first five seasons had Joe Cocker singing a verse and the chorus to "With A Little Help From My Friends". The final season had a musical version of the song without Cocker singing the verse. Just the chorus. The final season also had different visuals than earlier seasons.

[MyriVerse]

Dead Zone changed in the 4th season, getting rid of the great Jeff Buckley tune.
Alice changed lyrics at least once.
Baywatch got a new theme when it went into syndication (don't know if that counts).
The Avengers got a new theme when the awesome Diana Rigg came.
I think Three's Company had a different arrangement somewhere in its run.
Buffy's musical episode had a different theme.
Black Adder had a different theme each season.
Days of Our Lives had a different theme for 2004, but people didn't like it, so it switched back.
HIMYM had a few special episodes with different versions of the theme.
Red Dwarf had some special episodes, as well.
3rd Rock from the Sun too.
Young Ones had that horror episode.

[Güicho]

Super Friends changed with most incarnations
As did Scobby Doo with new seasons - https://www.youtube.com/watch?v=ChNmaeY_Sos
(although you could argue they are different shows)
Wonder Woman changed when they moved to another channel and went from WWII to a contemporary setting.

[KCJ506]

Cosby Show had a different theme every season. Season 7 being the exception which had the previous season's theme. The one that was used for Season 8 was supposed to be the previous one, but there were legal issues regarding the background mural.

The Family Ties theme sounded different on it's first season than it did in all the proceeding seasons.

Some Nicktoons such as Rocko's Modern Life and Hey Arnold had their themes remixed in later seasons.

SWAT Kats had a different theme in both of it's seasons.

Facts Of Life had it's theme remixed several times. In fact(no pun intended), some of the lyrics for the first season were sung by Charlotte Rae.

The Muppet Show had the same theme song, but it's opening was much different in the first season. It would end with Gonzo hitting the show sign's letter O like a gong whereas the rest of the seasons had him inside the letter O and trying to play a horn with various results. The last season also included an extra verse by Statler and Waldorf about how they keep going to the show despite their hatred of it.

[Comic-Reader Lad]

Super Friends changed with most incarnations
As did Scobby Doo with new seasons - https://www.youtube.com/watch?v=ChNmaeY_Sos
(although you could argue they are different shows)
Wonder Woman changed when they moved to another channel and went from WWII to a contemporary setting.

With Superfriends, the Wendy-Marvin theme was actually completely different from the Zan-Jayna themes even though they feel the same in spirit. All Superfriends themes from "All-New Super Friends Hour" forward were just variations of each other.

[Cyke]

Doctor Who was already brought up, but I just wanted to post this video as an example of a theme show keeping the same motif but just covering it (or even rearranging it) differently.



In comparison to other shows that change the whole song altogether, which is also very well cited in this thread.

[AnakinFlair]

Legends of Tomorrow has had a few themes- the original good theme, the current bad theme, and the crossovers-where they always tried to combine the themes of each show- had a variation of the original theme.

Arrow's theme also subtly changed on occasion.

[Somecrazyaussie]

Baywatch got a new theme when it went into syndication (don't know if that counts).

Came here to post this myself. From memory, It had a different theme for its first two seasons. Then it switched to the more famous theme by Jimi Jameson when it switched networks.

Walker, Texas Ranger started with a generic instrumental arrangement. But it changed from the second season onwards to the more popular one with Chuck singing the song.

[Jim Kelly]

Back in the day when shows were already in syndication while they were still running on the main network, they didn't just change the openings, they changed the titles. For example, in syndication BONANZA was PONDEROSA. Used to watch PONDEROSA every weekday afternoon after I came home from school.

[caj]

Land of the Lost changed it's wording for the theme song in season 3 for obvious reasons when Uncle Jack replaced their dad, Rick Marshall after he left the show.

[LoganAlpha30X33]

Well when it aired on tv didn't Dawson's Creek have one song that they used for the theme song only to then change it on all of the dvd's for monetary reasons or something along those lines...

[AndrewCrossett]

Sigmund and the Sea Monsters changed its theme, too... I think the Beach Boys threatened to sue them because the first one sounded too much like "California Girls."