Andrew Keir as Prof. Bernard Quatermass

James Donald as Dr. Mathew Roney

Barbara Shelley as Barbara Judd

Julian Glover as Colonel Breen

Bryan Marshall as Captain Potter

Maurice Good as Sergeant Cleghorn

Duncan Lamont as Sladden

Peter Copley as Howell

Edwin Richfield as Minister

Grant Taylor as Police Sergeant Ellis

Noel Howlett as Abbey Librarian

Thomas Heathcote as Vicar

Robert Morris as Jerry Watson

Bee Duffell as Miss Dobson

Sheila Steafel as Journalist

Hugh Futcher as Sapper West

Hugh Morton as Elderly Journalist

Hugh Manning as Pub Customer

June Ellis as Blonde

Keith Marsh as Johnson

James Culliford as Corporal Gibson

Roger Avon as Electrician

Brian Peck as Technical Officer

John Graham as Inspector

Charles Lamb as Newsvendor

David Savile as Army Officer

William Ellis as Journalist

Gareth Thomas as Workman (uncredited)

Elroy Josephs as Black Workman (uncredited)

Michael Poole as Older Workman (uncredited)

Albert Shepherd as Loader (uncredited)