The catalytic properties of lanthanum-containing bizeolite catalysts, based on a Pentasil-type high-silica zeolite and natural mordenite, in the thermal catalytic conversion of hydrocarbon feedstock were studied for the purpose of manufacturing C-2-C-4 olefin hydrocarbons. It was shown that the bizeolite catalysts hold promise for producing C-2-C-4 olefins (up to 55.0 wt % in total) from gas condensates. Methods for controlling the product composition by changing the mass ratio of the zeolites and the catalyst steaming conditions were proposed.