Polymerizable quaternary allyl-pyrimidinium salts, that is, 1-allyl-4-amino-5-phenyl-pyrimidine (IV), 1-allyl-4-acetamido-5-phenyl-pyrimidine (V), 1-allyl-5-hydroxymethylamino-5-phenyl-pyrimidine (VI), and 1-allyl-pyrimidine (VIII) bromides, as well as 4-acrylamido-5-phenyl-pyrimidines IIЈ and IVЈ, were synthesized and characterized. Three of the activated pyrimidine derivatives, the two acrylamido and one allyl pyrimidine, were immobilized onto (Agar-g-co-HEMA)-X-TMPTA via graft copolymerization. Each copolymer system, based on 2-hydroxyethyl methacrylate (HEMA) grafted onto Agar followed by crosslinking with trimethyllopropane triacrylate (TMPTA), was prepared by radiation-induced copolymerization carried out in the simultaneous mode. The release properties of the immobilized pyrimidines were assessed in various aqueous media over a period of approximately 22 days.