Abstract: A method for producing optical rod-shaped graded-index polymer preform by making the composition of the preform near the core differ from the composition of the shell of the preform by polymerization with rotation of a mixture containing the starting substances, whereby a mixture comprising various monomers is rotated and that after achieving a distribution of the monomers, the polymerization is carried out with rotation of the mixture, or that a monomer and thermoplastic polymer-containing mixture, whereby said monomer is different from the monomer from which said polymer has been prepared, is rotated and that, after achieving a distribution of said monomer and polymer, the monomer present in said mixture is subsequently polymerized with rotation, in which both cases the rotation is carried out with a diameter dependent rotation velocity, represented by the following general equation: rpm>10,000 d.sup.-0.5 wherein: rpm=rotation velocity, revolutions per minute d=diameter of the preform (cm).