[en] WWER reactors have traversed a long way since the installation of Novovoronez-1 reactor in 1964 from WWER-210 MW to WWER-365 MW, to WWER-440 MW, to the latest version of WWER-1000 MW. At present WWER-440 MW and WWER-1000 MW contribute the major source of nuclear power from WWER reactors. Even though, pressure vessel steels of western origin (A533B and A508) are distinguishable by their chemical compositions vis-a-vis WWER pressure vessel steels, irradiation response of these two steels are coincidentally similar, provided the key deleterious element contents are similar. However, the swapping of Russian Code/Guide with the Codes/Guides recommended for the evaluation of embrittlement of pressure vessel steels of western origin would be unreliable because of the obvious bias of the data base with respect to the extended fluence range, and because of the influence of difference relative amounts of copper and phosphorous in WWER pressure vessel steels vis-a-vis in western pressure vessel steels need to-be understood and interpreted from the data base of these steels. The paper attempts to elaborate on the studies of embrittlement of the WWER steels and summarizes the present status of information on these steels. (author)