John Phillip Law
Diabolik

Marisa Mell
Eva Kant

Michel Piccoli
Inspector Ginko

Adolfo Celi
Ralph Valmont

Claudio Gora
Police Chief

Mario Donen
Sgt. Danek

Renzo Palmer
Mr. Hammond

Caterina Boratto
Lady Clark

Lucia Modugno
Prostitute

Annie Gorassini
Rose

Carlo Croccolo
Lorry Driver

Lidia Biondi
Policewoman

Andrea Bosic
Bank Manager

Federico Boido
Joe

Tiberio Mitri
Valmont's Henchman #1

Isarco Ravaioli
Valmont's Henchman #2

Giorgio Sciolette
Dr. Ferrar

Terry-Thomas
Minister of Interior / Minister of Finance

Giulio Donnini
Dr. Vernier (uncredited)

Edward Febo Kelleng
Sir Harold Clark (uncredited)

Sandro Dori
Stud (uncredited)

Giorgio Gennari
Rudy (uncredited)

Giuseppe Fazio
Tony (uncredited)

Massimo Ciprari
Fake Diplomat (uncredited)

Franco Bellucci
Fake Diplomat (uncredited)

Orlando Pallamari
Mr. Hammond's Secretary (uncredited)

Francesco Mulè
(uncredited)

Angela Palmieri
Dr. Vernier's Nurse (uncredited)

Milena Zampana
Party Guest (uncredited)

Raniero Dorascenzi
Party Guest (uncredited)

Vezio Natili
Party Guest (uncredited)

Lella Cattaneo
Party Guest (uncredited)

Renzo Granelli
Party Guest (uncredited)

Mario Ingrassia
Party Guest (uncredited)

Filippo Perego
Party Guest (uncredited)

Augusto Innocenzi
Party Guest (uncredited)

Domenico Ravenna
Party Guest (uncredited)

Silvio Klein
Journalist at Press Conference (uncredited)

Oscar Sciamanna
Journalist (uncredited)

Regina Elena Bisio
Old Woman at the Morgue (uncredited)