A method is presented of a random control of the radionuclide purity of deliveries of99mTc sodium pertechnate pro inj. from the extraction generator of the Institute of Nuclear Research in Řež. Results are shown of measuring values of activities (in percentage) of the contaminants99Mo,131I,69Co and188Re from 1983 to 1986 and after adjusting the technology of the production in 1987. Values of the activity in percentage of the contaminants of deliveries of99mTc solutions from the generator99Mo-99mTc of the Institute of Nuclear Research with99Mo separated from fission products at the Institute of Nuclear Research in Řež and that separated from fission products in the Zentralinstitut für Kernforschung — Dresden are compared with values of the activity (in percentage) of contaminants of eluates from radionuclide clution generators99Mo-99mTc AMERTEC II. Elution generators were made in the Zentralinstitut für Kernforschung — Dresden and elution generator MTc-G-3 from the Isotope Production and Reactor Centre Swierk — Poland.