In many of the newer episodes, Michaelangelo used a grappling hook as his weapon instead of his traditional nunchauks. This is because nunchauks were outlawed in many countries and since the show went international, they changed it for everyone.
In the original comics, all four turtles had red bandanas. For the TV show, they were each given a different color to make it easier to tell them apart.
The show was re-named "Teenage Mutant Hero Turtles" for its UK transmission, because it was thought that the connotations of the word "ninja" were too violent.
At the time of its final episode, it was the longest running cartoon in American TV history. However this record was beaten two years later by "The Simpsons" (1989).
As humans, Bebop was African-American and Rocksteady was blond.
For Season 4, 28 episodes were produced for syndication and 26 episodes were produced for CBS' "Kid TV" Saturday morning line up. However, of 15 of the syndicated episodes never aired in 1990. The "European Vacation" episodes were not seen in the United States until USA Network started showing reruns in late 1993 and the "Awesome Easter" episodes weren't seen until 1991. An easy way to tell that these are Season 4 episodes is: the original intro is used, title cards are used, the closing credits uses the still image that debut that season, and the Technodrome is stuck on an asteroid in Dimension X. The most likely these episodes were delayed was because of animation or schedule problems.