The following is a list of television shows that had spinoffs or are a spinoff themselves.
To be a spinoff, the show must be derived from the original (or a spinoff of the original), based on a character (like Mork, episode (Happy Days), or a historical connection (Young Maverick). Revivals (The New Leave it to Beaver), British-to-American conversions (Steptoe and Son) and cartoon spinoffs of live action shows (The Fonz and the Happy Days Gang) are not considered spinoffs.
This list does not include Saturday morning or after school cartoons (like Batman : The Animated Series), nor does it include strictly cross-overs (like when Michael Richards (as Kramer) appeared on Mad About You), nor daytime soap operas (The Bold and the Beautiful), nor shows originating outside of North America (Doctor Who).
They are ordered like so:
If you want to read a write up for most of the spinoffs below, please visit "http://home.earthlink.net/~jinxo/maincrosslist.html" (by Thom Holbrook), an invaluable source for filling in the holes in this list. Not only do the writeups provide the necessary information, quite often they are damn funny, too.
Addition February 25 2001
Addition October 1 2002
Added Law and Order : Criminal Intent
Added Star Trek : Enterprise