Authors studied a method of thermolytic conversion of waste polyolefins in an innovative packed bed reactor which operates on the principle of a distillation column. Vapors of cracked polymers, with a boiling point below 360 degrees C, are transported with the use of a carrier gas to the next reactor where they are catalytically hydrogenated under atmospheric pressure using syngas. Waste polyolefins obtained from the landfill were used as a raw material. To determine the effect of the carrier gas composition on the quality of the liquid fraction, nitrogen, syngas, and its mixtures were used in conducted experiments. The chemical, composition and the selected physicochemical properties of the liquid product were investigated in the laboratory. Mixtures of nitrogen and syngas were tested as a carrier gas which also played the role of the hydrogenation agent in the whole process. Conducted research indicated that the best level of hydrogenation was obtained when only syngas was used as the carrier gas in the cracking reactor and as the hydrogen donor during hydrogenation. The obtained liquid product can be distilled into diesel fuel and gasoline fractions which can be used for fuel production.