Al Pacino as Officer Frank Serpico

John Randolph as Sidney Green

Jack Kehoe as Tom Keough

Biff McGuire as Captain McClain

Barbara Eda-Young as Laurie

Cornelia Sharpe as Leslie Lane

Tony Roberts as Bob Blair

John Medici as Pasquale

Allan Rich as D. A. Tauber

Norman Ornellas as Rubello

Edward Grover as Lombardo

Albert Henderson as Peluce

Hank Garrett as Malone

Damien Leake as Joey

Joseph Bova as Potts

Gene Gross as Captain Tolkin

John Stewart as Waterman

Woodie King Jr. as Larry

James Tolkan as Steiger

Ed Crowley as Barto

Bernard Barrow as Palmer

Sal Carollo as Mr. Serpico

Mildred Clinton as Mrs. Serpico

Nathan George as Smith

Gus Fleming as Dr. Metz

Richard Foronjy as Corsaro

Alan North as Brown

Lewis J. Stadlen as Berman

John McQuade as Kellogg

Ted Beniades as Sarno

John Lehne as Gilbert

M. Emmet Walsh as Gallagher

George Ede as Daley

Charles White as Delaney

F. Murray Abraham as Detective Partner (uncredited)

P.J. Benjamin as Man (uncredited)

Don Billett as Detective Threatening Serpico (uncredited)

Val Bisoglio as Weapons Storage Officer (uncredited)

John Brandon as Police Lieutenant (uncredited)

James Bulleit as Det. Styles (uncredited)

Roy Cheverie as Cop (uncredited)

Sam Coppola as Cop (uncredited)

Marjorie Eliot as Rape Victim (uncredited)

René Enríquez as Cervantes Teacher (uncredited)

Conard Fowkes as Cop - Narcotics Raid (uncredited)

Frank Gio as Police Lieutenant (uncredited)

Trent Gough as Cop (uncredited)

Paul E. Guskin as Police Academy Classmate (uncredited)

Nick Hardin as Television Cameraman (uncredited)

Judd Hirsch as Cop (uncredited)

Richard Kuss as Detective (uncredited)

Tony Lo Bianco as Cop (uncredited)

George Loros as Det. Glover (uncredited)

Kenneth McMillan as Charlie (uncredited)

Stephen Pearlman as Desk Sergeant (uncredited)

Tim Pelt as Black Hood (uncredited)

William Pelt as Black Hood (uncredited)

Jay Rasumny as Television Cameraman (uncredited)

Franklin Scott as Black Prisoner (uncredited)

Tom Signorelli as Bookmaker (uncredited)

Ben Slack as Detective Sitting At Desk (uncredited)

Jaime Sánchez as Cop (uncredited)

Tracey Walter as Street Urchin (uncredited)

Mary Louise Weller as Sally - Girl at Party (uncredited)

Judd Omen as Doctor