Antonio Cantafora as Paul

José Luis Ayestarán as Kronos/Supersonic Man

Cameron Mitchell as Dr. Gulik

Diana Polakov as Patricia Morgan / Patricia Gordon

José María Caffarel as Prof. Morgan / Prof. Gordon

Frank Braña as Peterson

Javier De Campos as Drunk

Tito García as George

Luis Barboo as Harrison

Quique Camoiras as Bill

Ángel Ter as

Emilio Higuera as

Luis Castilla as

Emilio Fornet as

Marta Fernández Muro as

José Antonio Rico as

Teófilo Martínez as (voice)

Óscar Simón as