A paraffin oil (b. 189.7-210.3 degrees C) was converted to arom. hydrocarbons (mostly PhMe and m-Me(2)C(6)H(4)) by zeoforming on zeolite catalysts at 380-410 degrees C in 2 tubular flow reactors. The yields of gaseous, gasoline (b. below 210 degrees C) and oil fractions were 37.1-37.8%, 52.9-54.8% and 8.1-9.3%, resp. The gasoline fractions met the std. requirements (octane no., S content, vapour pressure) except for content of arom. hydrocarbons (51.6-52.2%) higher than allowed.