A combined promoting effect of lanthanum and molybdenum on the catalytic properties of high-silica zeolite in natural gas conversion into liquid hydocarbons has been studied. It has been shown that lanthanum additives to the Mo-containing zeolite lead to an increase in the activity and selectivity of a catalyst in the formation of aromatic hydrocarbons from the components of natural gas. It has been found that the maximum amount of aromatic hydrocarbons are formed in the presence of a zeolite containing 1.0% La and 4.0% Mo. Using thermal desorption of ammonia, data has been obtained on the amount and strength of acid sites in modified zeolites.