2004

2004 was a big year for Cartoon Network. The Powerhouse theme is replaced with CN City. The logo is explicitly abbreviated as "CN". Two new shows, Foster's Home for Imaginary Friends and Hi Hi Puffy AmiYumi, premier. Johnny Bravo, Samurai Jack, and Evil Con Carne conclude this year.

20

 * Johnny Bravo premieres its fourth and last season with the episode "Johnny Bravo Goes to Hollywood".

5

 * ¡Mucha Lucha!​ premieres.

26

 * Star Wars: Clone Wars premieres its second season with the episode "Chapter 11".

16

 * The Powerpuff Girls premieres its sixth and last season with the episode "Prime Mates/Coupe D'Etat". In addition, Toonami airs on a weekday for the final time.

17

 * The Saturday version of Toonami debuts, replacing Saturday Video Entertainment System.

19

 * A new weekday afternoon block called Miguzi debuts, replacing the weekday version of Toonami.

1

 * Megas XLR premieres with the episode "Test Drive".
 * May Movie Month airs until May 31st.

29

 * Justice League ends with the episode "Starcrossed".

4

 * Season 2 of Codename: Kids Next Door ends with the episode "Operation: E.N.D.".

11

 * Codename: Kids Next Door premieres its third season with the episode "Operation: F.U.T.U.R.E.".

13

 * Cartoon Network's Cartoon Theatre, featuring Osmosis Jones, aired with its original look for the last time.

14

 * Cartoon Network launches the CN City look, replacing Powerhouse.

18

 * The set of Fridays is revamped for the City era.

19

 * The bumpers for Cartoon Network's Cartoon Theatre are revamped for the City era. The block's announcer, the late Don LaFontaine, is replaced by the channel’s new female announcer, Nikki. Ed from Ed, Edd n Eddy is also added as a movie theatre usher.
 * Saturday Block Party debuts.

20

 * The bumpers for The Cartoon Cartoon Top 5 are revamped for the City era, and is renamed to simply the "Top 5".

31

 * A spin-off to Justice League, titled Justice League Unlimited premieres with the episode "Initiation".

13

 * Foster's Home for Imaginary Friends premieres with the TV movie "House of Bloo's".

27

 * Johnny Bravo ends with the episode "Johnny Makeover/Back on Shaq".
 * The Powerpuff Girls has paused premiereing new episodes with the episode "Roughing It Up/What's the Big Idea?".

28

 * Season 1 of Megas XLR ends with the episode "Coop D'Etat".

29

 * Atomic Betty premieres with the episode "Atomic Roger/Toxic Talent".

25

 * Samurai Jack ends with episode "Jack and the Baby".

1

 * Evil Con Carne premieres its second and last season with the episode "No No Nanook".

2-3

 * The Looney Tunes and Merrie Melodies shorts as well as the Boomerang block are removed from the schedule altogether due to the box office failure of Looney Tunes: Back in Action.

16

 * Megas XLR premieres its second and last season with the episode "Ultra Chicks".

22

 * Evil Con Carne ends with the episode "Hector, King of the Britons". The series was cancelled due to low ratings as it was out-populated by Maxwell Atoms' other work, The Grim Adventures of Billy & Mandy.

5

 * Season 4 of Ed, Edd n Eddy ends with the episode "Take This Ed and Shove It".

12

 * Season 3 of Codename: Kids Next Door ends with the episode "Operation: S.P.R.O.U.T./Operation: H.O.U.N.D.".

19

 * Hi Hi Puffy AmiYumi premieres with the episode "Dis-Harmony/Collect All 5/Ninjcompoop".
 * Codename: Kids Next Door premieres its fourth season with the episode "Operation: R.A.B.B.I.T./Operation: F.L.U.S.H.".

29

 * A Cartoon Network Christmas begins, and lasts until December 25th.

27

 * Winter Break begins, and lasts until December 31st.