The present study evaluates the use of short PET fibres as a reinforcement of polypropylene matrix. The main application of the developed composite compound are injection moulded goods. An earlier study found that the main drawback of PET fibres is their loss of mechanical performance after exposure to elevated temperature, which occurs during compounding and injection moulding . For this reason the thermostable grade of PET fibres was selected for manufacturing of a composite, which was carried out at the lowest possible temperature. That gave considerable increase in terms of a composite’s impact strength. Its strength was from two- to three times higher than that of its counterpart reinforced with the same weight content of glass fibres.