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

John Wynn

Detective Sergeant Best

Harold Lang

Christie

Lionel Jeffries

Blake

Thora Hird

Rosie Wrigley

Sam Kydd

Police Sergeant Questioning Rosie

Jane Asher

Little Girl (uncredited)

Toke Townley

The Chemist (uncredited)

Gordon Jackson

BBC TV producer

Margaret Anderson

Maggie (uncredited)

Eric Corrie

Maggie's Boyfriend (uncredited)

Henry B. Longhurst

George, Maggie's father (uncredited)

Ernest Hare

Crash Site Fire Chief (uncredited)

Michael Godfrey

Crash Site Fireman (uncredited)

Marianne Stone

Central Clinic Nurse (uncredited)

John Kerr

Photo Lab Technician (uncredited)

Bartlett Mullins

Zookeeper (uncredited)

Mayne Lynton

Zoo Superintendent (uncredited)

Barry Lowe

Nurse Tucker (uncredited)

Jane Aird

Mrs. Lomax (uncredited)

Molly Glessing

Mother at Zoo (uncredited)

Arthur Gross

TV Show Floor Director (uncredited)

Basil Dignam

Sir Lionel Dean (uncredited)

Donald Gray

TV Program Announcer (uncredited)

Gron Davies

Charles Greene (uncredited)

Stanley Van Beers

Ludwig Reichenheim (uncredited)

Arthur Lovegrove

Sergeant Bromley (uncredited)

James Drake

Sound Engineer (uncredited)