• 
  Sidney Lumet

  regizor

• 
  Peter Maas

  scenarist
• 
  Waldo Salt

  scenarist

• 
  Al Pacino

  Frank Serpico
• 
  F. Murray Abraham

  Detective partner
• 
  John Randolph

  Sidney Green
• 
  Jack Kehoe

  Tom Keough
• 
  Biff McGuire

  Captain McClain

• 
  Allan Rich

  Dist. Atty. Herman Tauber
• 
  George Loros

  Det. Glover
• 
  Stephen Pearlman

  Desk sergeant
• 
  Tom Signorelli

  Bookmaker
• 
  Judd Hirsch

  Poliţist
• 
  M. Emmet Walsh

  Chief Gallagher
• 
  Ed Crowley

  Barto

• 
  James Tolkan

  Lt. Steiger
• 
  Tony Roberts

  Bob Blair
• 
  Kenneth McMillan

  Charlie
• 
  Richard Foronjy

  Rudy Corsaro
• 
  Don Billett

  Detective threatening Serpico
• 
  Frank Gio

  Police lieutenant
• 
  John Brandon

  Police lieutenant
• 
  Damien Leake

  Joey
• 
  Alan North

  Brown
• 
  Ted Beniades

  Al Sarno
• 
  Sam Coppola

  Poliţist
• 
  Tony Lo Bianco

  Poliţist
• 
  Tim Pelt

  Black hood
• 
  Joseph Bova

  Potts (as Joe Bova)
• 
  Barbara Eda-Young

  Laurie
• 
  Hank Garrett

  Malone
• 
  Edward Grover

  Lombardo (as Ed Grover)
• 
  Albert Henderson

  Peluce (as Al Henderson)
• 
  John Medici

  Pasquale
• 
  Norman Ornellas

  Rubello
• 
  Cornelia Sharpe

  Leslie