When the show was canceled in 1966, the producers gave Morticia's oval-backed wicker chair to Carolyn Jones as a memento. Jones kept it in her bedroom for the rest of her life.
The interior of the Addams house was inspired by the real-life Manhattan apartment of Charles Addams, which contained suits of armor, an antique crossbow collection, and other oddities.
Carolyn Jones and John Astin decided to give Gomez and Morticia "a grand romance" as an antidote to the virtually asexual parents then common in television shows.
Originally, Lurch was supposed to be largely silent with only groaning. However, during shooting, Ted Cassidy improvised the line, "You rang?" in a scene where the family rang the servant bell. The perfect timing and Cassidy's deep voice of that line went over so well that Lurch was rewritten to have dialogue, which mainly consisted of short, repetitive sentences.
Jackie Coogan was originally rejected as Uncle Fester. He went home, shaved his head, and did his own Fester makeup and costume. This won him the part.