Brian Donlevy

Prof. Bernard Quatermass

Richard Wordsworth

Victor Carroon

David King-Wood

Dr. Gordon Briscoe

Jack Warner

Inspector Lomax

Margia Dean

Judith Carroon

Maurice Kaufmann

Marsh

Harold Lang

Christie

Lionel Jeffries

Blake

Thora Hird

Rosie Wrigley

Sam Kydd

Police Sergeant Questioning Rosie

Gordon Jackson

BBC TV producer

Jane Asher

Little Girl (uncredited)

Toke Townley

The Chemist (uncredited)

Marianne Stone

Central Clinic Nurse (uncredited)

John Kerr

Photo Lab Technician (uncredited)

Basil Dignam

Sir Lionel Dean (uncredited)

Donald Gray

TV Program Announcer (uncredited)

Stanley Van Beers

Ludwig Reichenheim (uncredited)

James Drake

Sound Engineer (uncredited)