* The "Inmates":
* Gary Kent as "Joe"
* Marianna Hill as "Carol"
* Michael Margotta as "Dave"
* Anthony Zerbe as "Will"
* The "Guards":
* Vic Morrow as "Captain"
* Charles Durning as "Sergeant"
* John Rubinstein as "Lieutenant"
* William Schallert as "Mr. Jones"
This was a low-budget film and didn't have a large cast. While these are the main actors, there were a few other smaller roles filled by other actors as well.