Kinetics of transformation of PCBs and the formation of gas products (H₂, CO, CO₂, CH₄, C₂H₆, C₂H₄, ∑C₃, ∑C₄, ∑C₅, ∑C₆) has been studied during the radiolysis of transformer oil of "Sovtol" mark with concentration 165.4 g/kg identified PCB by us. It is established that the number of PCBs increases at up to 5 Mrad radiation dose, and the decreasing is observed at increase in radiation doses. PCBs undergo 55% mass transformation up to 50 Mrad dose. The main gas product of the radiolysis is carbon dioxide (0.03 mo­lecule 10^-2 eV), hydrogen (0.012 molecule 10^-2 eV) and carbon monoxide (0.007 molecule 10^-2 eV).