The following is the list of Sci-fi References in Seinfeld.
- "The Foundation" makes several references to Star Trek. Jerry's line to Susan's parents, "She's not really dead if we find a way to remember her," is very similar to a line said at the end of Star Trek II: The Wrath of Khan ("He's really not dead. As long as we remember him.").
- Kramer mentions his Katra, the Vulcan spirit introduced in Star Trek III: The Search for Spock.
- Finally, when George learns of the foundation, he yells "Khaaaaaaannnnnnn!!!" while the camera pans above him, much like Captain Kirk in Star Trek II.
- In "The Calzone", Elaine makes a bet with Todd Gack about whether or not Dustin Hoffman was in Star Wars. Gack loses the bet and buys Elaine dinner.