The protagonists of the film are two brothers - Smaller and Big, Filomena and the dog Klops. Big has problems at school, so he decides to run away from home. His brother decides to find him.
| Actor | Role |
|---|---|
| RRobert Schmidt'Mniejszy' | 'Mniejszy' |
| MMagda NałęckaFilomena | Filomena |
| TTadeusz Drewnowski'Duży' | 'Duży' |
| GGrzegorz PrzybylskiMietek | Mietek |
| PPiotr Krawczyk'Trąbka' | 'Trąbka' |
 Henryk BąkNeighbour | Neighbour |
 Henryk BorowskiNarrator (voice) | Narrator (voice) |
 Roman KłosowskiKowalski | Kowalski |
 Anna CiepielewskaMommy | Mommy |
 Jan KociniakMister Józio | Mister Józio |
| AAndrzej KrasickiMercedes owner | Mercedes owner |
 Eliasz KuziemskiDirector | Director |
 Zdzisław LeśniakBartolomeo | Bartolomeo |
 Wiesław MichnikowskiDaddy | Daddy |
 Igor PrzegrodzkiActor | Actor |
 Mieczysław VoitMarkuszewski | Markuszewski |
| GGrażyna TorbickaFilomena's friend (uncredited) | Filomena's friend (uncredited) |
 Konrad NałęckiFilm director (uncredited) | Film director (uncredited) |