The cracking of the waxes obtained in the flash pyrolysis of polypropylene has been studied in laboratory FCC units under the standard conditions in FCC (fluid catalytic cracking) units. The reaction equipment is provided with a riser simulator reactor, and the experiments have been carried out using a commercial equilibrium catalyst, with a catalyst/feed ratio of C/O = 5.5, in the 500-550 degrees C range and for contact times between 3 and 12 s. The effect of these operating conditions on the yields of products and on the composition of gas and gasoline lumps has been studied. The results have been compared with those of VGO (vacuum gas oil) cracking, which is the standard FCC feed in refineries, and with those of a mixture of VGO (80 wt %) and waxes (20 wt %).