Director Edgar Wright is to helm the picture, which is set for release July 31, 2015.
Details of the film's plot are being kept under wraps.
"When Edgar Wright came to us with the idea of Paul Rudd, we felt a huge sense of relief because the first step in creating any Marvel Studios film is finding the right star," Marvel's Kevin Feige said in a statement. "We knew early on that we had found the right person in Paul. When he not only agreed to do it but became as enthusiastic as any actor we'd ever met with about doing the work, we knew we'd found the right guy. We couldn't be more excited for our audiences to see what he's going to do to bring Ant-Man to life."
Rudd's film credits include "This Is 40," "I Love You, Man," "Role Models," "Forgetting Sarah Marshall," "Our Idiot Brother," "Knocked Up," and "The 40-Year-Old Virgin."