A search for human protein kinase CK2 inhibitors in a series of new amino-substituted pyrido[2,3-d]pyrimidine derivatives. Methods. Organic synthesis, analytical and spectral methods, molecular docking, in vitro biochemical testing. Results. Synthesis of new pyrido[2,3d]pyrimidine derivatives with various aminogroups in position[s] 4 and 6 of the heterocycle was developed. Two compounds inhibiting kinase CK2 in micromolar concentrations were found among these derivatives. Conclusion. New pyrido[2,3-d]pyrimidin-7-ones containing aminogroups in position[s] 4 and 6 of heterocyclic system and new 4-amino-substituted pyrido[2,3-d]pyrimidin-7-amine derivatives have been synthesized. The inhibition activity of new pyrido[2,3-d]pyrimidines has been examined and the optimization modes have been suggested. Methyl-2-[(7-aminopyrido[2,3-d]pyrimidine-6-yl)amino]benzoate and N-(4-anilino-7oxo-7,8-dihydropyrido[2,3-d]pyrimidine-6-yl)-3,4-dimethoxy-benzamide were found to inhibit protein kinase CK2 at IC50 of 6 and 19.5 μМ, respectively.