Radiation crosslinking of bisphenol-a polycarbonate (PC) was carried out by the gamma-irradiation of the polymeric films containing 5 and 2 wt % of bisphenol-a dimethacrylate (BPDMA) or triallyl cyanurate, respectively, as well as by the BPDMA grafting from acetone solution onto PC preirradiated in air. The modified samples were analyzed for the sol/gel content, and the dependences of gel fraction yield of crosslinked polymer on monomers concentration and absorbed dose were found. The radiation-chemical yields of crosslinking and degradation as well as gelation doses were determined for the modified PC. Molecular weights of the starting and irradiated pure PC were detemined by the GPC method, and radiation-chemical yield of PC degradation was calculated. It has been found essential difference in efficiency of PC crosslinking depending on monomers and doses used as well as on methods of modification. Effects of crosslinking agents distribution in the PC matrix and simultaneous processes of crosslinking and degradation in the polymer-monomer compositions on efficiency of PC crosslinking have been discussed.