Efficiency of reduction of PCBs in aqueous solution was examined with bimetallic catalyst Fe-C/Pd consisting of palladized grey cast iron and with a new trimetallic catalyst (Cu-Fe-C/Pd) consisting of a copper metal plate with microparticles of palladized grey iron (bimetallic catalyst). PCB solutions were prepared using DELOR 103. The trimetallic catalyst was significantly efficient than bimetallic one. Trimetallic catalyst reduced the concentration of PCB to approximately 1% of its initial value during 70 minutes and bimetallic during 240 hours. More than 20% of unreacted PCBs were found adsorbed on the surfaces of the bimetallic catalysts. Presence of metal copper accelerates formation of the oxidation products and their release from the catalyst surface as the flocks recovers activity of the trimetallic catalyst. It means the reductive dechlorination of PCB is not the only decisive control step in the reduction of PCB in water by zero valence metals.