According to the invention, the process for making tube-shaped, radioactive light sources is characterized by the fact that a glass tube containing a Luminophor and a radioactive gas, is subdivided successively into glass tube sections intended for use as radioactive light sources, by means of a laser beam. This is accomplished with a closely localized lazer beam so that a sufficient quantity of glass is drawn from the sidewalls to form end walls, to devide the sealed tube and simultaneously seal the ends of the two tubes produced without loss of radioactive gas therein.