Rapeseed oil was converted on ZSM-5 zeolite catalyst at 200-300 degrees C and 1.7 MPa under N-2 and then hydrorafined at 320 degrees C and 3.0 MPa under H-2 to produce a hydrocarbon fuel component with an increased content of iso-paraffins. The zeoforming resulted in a decrease of cloud point temp. of a mixt. of com. crude oil fraction b. 160-245 degrees C and the zeo-formate (20%) down to -10.2 degrees C (from -6.2 degrees C).