The antioxidant activity of novel N 3 and C 6 substituted 5,7-dimethyl-3H-thiazolo [4,5-b]pyridine-2one derivatives was evaluated in vitro by the method of scavenging effect on 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. The correlation analysis between the antioxidant activity and different subsets molecular descriptors was carried out for 19 compounds. The regression models derived with QSAR-analysis display the significant influence of topological structure, atom and bond type counts, physicochemical properties, and quantum-chemical structure parameters on the free radical scavenging effect of the compounds.