John Phillip Law as Diabolik

Marisa Mell as Eva Kant

Michel Piccoli as Inspector Ginko

Adolfo Celi as Ralph Valmont

Claudio Gora as Police Chief

Mario Donen as Sgt. Danek

Renzo Palmer as Mr. Hammond

Caterina Boratto as Lady Clark

Lucia Modugno as Prostitute

Annie Gorassini as Rose

Carlo Croccolo as Lorry Driver

Lidia Biondi as Policewoman

Andrea Bosic as Bank Manager

Federico Boido as Joe

Tiberio Mitri as Valmont's Henchman #1

Isarco Ravaioli as Valmont's Henchman #2

Giorgio Sciolette as Dr. Ferrar

Terry-Thomas as Minister of Interior / Minister of Finance

Giulio Donnini as Dr. Vernier (uncredited)

Edward Febo Kelleng as Sir Harold Clark (uncredited)

Sandro Dori as Stud (uncredited)

Giorgio Gennari as Rudy (uncredited)

Giuseppe Fazio as Tony (uncredited)

Massimo Ciprari as Fake Diplomat (uncredited)

Franco Bellucci as Fake Diplomat (uncredited)

Orlando Pallamari as Mr. Hammond's Secretary (uncredited)

Francesco Mulè as (uncredited)

Angela Palmieri as Dr. Vernier's Nurse (uncredited)

Milena Zampana as Party Guest (uncredited)

Raniero Dorascenzi as Party Guest (uncredited)

Vezio Natili as Party Guest (uncredited)

Lella Cattaneo as Party Guest (uncredited)

Renzo Granelli as Party Guest (uncredited)

Mario Ingrassia as Party Guest (uncredited)

Filippo Perego as Party Guest (uncredited)

Augusto Innocenzi as Party Guest (uncredited)

Domenico Ravenna as Party Guest (uncredited)

Silvio Klein as Journalist at Press Conference (uncredited)

Oscar Sciamanna as Journalist (uncredited)

Regina Elena Bisio as Old Woman at the Morgue (uncredited)