How many movies have Ivan Reitman and Peter Costanza collaborated on?

They have worked on 2 movies together! Their first movie together was Ghostbusters (1984) and was their highest rated movie together. They have not worked together since Private Parts (1997).

Crew
Director
Role
Man Fleeing Marshmallow Man (uncredited)
Crew
Producer
Role
Zuul / Slimer (voice) (uncredited)