Also Known As:
- 4 Flies on Grey Velvet
- 4 mouches de velours gris
- 4 myges se gri veloudo
- Cuatro moscas de terciopelo gris
- Den djävulska fällan
- Fire fluer på grå fløyel
- Four Flies on Grey Velvet
- Four Patches of Grey Velvet
- Fyra flugor på grå sammet
- Fyra flugor på grått sammet
- Neljä kärpästä harmaalla sametilla
- Quatre mouches de velours gris
- Quatro Moscas no Veludo Cinza
- Quattro mosche di velluto grigio
- Tesseris myiges se prasino veloudo
- Vier Fliegen auf grauem Samt
- Dario Argento
- Dario Argento
- Luigi Cozzi
- Mario Foglietti
- Michael Brandon ... Roberto Tobias
- Mimsy Farmer ... Nina Tobias
- Jean-Pierre Marielle ... Gianni Arrosio
- Bud Spencer ... Godfrey 'God'
- Aldo Bufi Landi ... Pathologist
- Calisto Calisti ... Carlo Marosi
- Marisa Fabbri ... Amelia, the maid
- Oreste Lionello ... The Professor
- Fabrizio Moroni ... Mirko
- Corrado Olmi ... Porter
- Stefano Satta Flores ... Andrea
- Laura Troschel ... Maria (as Costanza Spada)
- Francine Racette ... Dalia
- Dante Cleri ... Coffin Salesman
- Guerrino Crivello ... Rambaldi, the neighbor
- Gildo Di Marco ... Postman
- Tom Felleghy ... Police Commissioner Pini
- Leopoldo Migliori ... Musician
- Fulvio Mingozzi ... Music Studio Manager
- Stefano Oppedisano
- Pino Patti ... 2nd Funeral Exhibition Attendant
- Ada Pometti ... Lady on street
- Jacques Stany ... Psychiatrist
- Shirley Corrigan ... Girl at Party
- Luigi Cozzi ... Extra in subway / masked killer in theater
- Giovanni Di Benedetto ... Funeral Exhibition Visitor
- Sandro Dori ... 1st Funeral Exhibition Attendant
- Renzo Marignano ... 2nd Funeral Exhibition Attendant
- Diego Morreale ... Extra in subway / passerby in front of Roberto's house
- Anna Maria Perego ... Dalia's Mother
.