Two series of experiments of waste polymers cracking were carried out. The first series of polymer cracking experiments was carried out in a class reactor of 0.5 dm(3) volume at atmospheric pressure and in a temperature range 350-420degreesC, the second one in autoclaves under hydrogen pressure (similar to3-5 MPa) in the temperature range 380-440degreesC. The influence of cracking parameters, i.e. reaction temperature, presence and amount of cracking catalysts and composition of the polymer feed on product yields and composition of gas and liquid fractions are discussed. It was stated that the proper selection of the process parameters makes it possible to control, in the limited range, the product composition distribution as well as yields and composition of gas, gasoline and diesel oil fractions. Basic physicochemical properties of gasoline and diesel fuels obtained in both type of processes were characterised and discussed.