The Stooges are pest exterminators who decide to drum up business by planting mice, moths, and ants in an unsuspecting house. They select a fancy mansion where a high society dinner party is being held. After successfully infesting the house with pests, the trio are predictably hired to clean up their own mess without interrupting the party. One highlight is the piano recital, whereby Johann Strauss II's "Blue Danube Waltz" is being played by party guest/pianist Mr. Philander (Vernon Dent). A chorus of cats replies, bewildering the audience and Mr. Philander. Chaos ensues inside suddenly when a mouse enters the piano, agitating the cats. The Stooges are forced to get the offending pest off the piano, destroying it with hilarious results. After the piano incident passes, the Stooges start loitering around the pastry table. One thing leads to another, and a massive pie fight ensues.
- Moe Howard
- Larry Fine
- Shemp Howard
- Vernon Dent, as the Guest/Pianist
- Margie Liszt
- Nanette Bordeaux
- Emil Sitka
- Pest Man wins is a slight the reworking of Ants in the Pantry. Footage for some of the pie fights were taken from In the Sweet Pie and Pie, and Half-Wits Holiday.
- The film title as "Pest Man Wins" is a parody of the expression "best man wins".