威廉姆·霍珀

William Hopper

饰：Col. Robert Calder

弗兰克·普格利亚

Frank Puglia

饰：Dr. Leonardo

约翰·伦巴

John Zaremba

饰：Dr. Judson Uhl

托马斯·布朗·亨利

Thomas Browne Henry

饰：Maj. Gen. A.D. McIntosh

蒂托·沃洛

Tito Vuolo

饰：Police Commissioner Charra

简阿尔翁

Jan Arvan

饰：Contino (government official)

Arthur Space

饰：Dr. Sharman (XY21's chief scientist)

John Duke

John Duke

饰：Staff Officer in Pentagon (uncredited)

雷·哈里豪森

Ray Harryhausen

饰：Rome Zoo visitor (uncredited)

George Khoury

饰：Verrico (fisherman) (uncredited)

Rollin Moriyama

饰：Farmer (uncredited)

Don Orlando

饰：Mondello (fisherman) (uncredited)

乔治·佩林

George Pelling

饰：Maples (Reuters reporter) (uncredited)

Dale Van Sickel

饰：Maj. Stacy (Gen. McIntosh's aide) (uncredited)

琼·泰勒

Joan Taylor

饰：Marisa Leonardo

Bart Braverman

Bart Braverman

饰：Pepe (as Bart Bradley)

Sid Cassel

饰：Farmer (first victim) (uncredited)

Jerry Riggio

威廉·伍德森

William Woodson

James Dime

Noel Drayton

Barry Russo

Saverio LoMedico