The effects of nuclear data uncertainties (cross sections, neutron emissions, fission yields, and decay data) on the burnup of a typical pressurized water reactor fuel element are presented in this paper. The uncertainties on reactivity swing, inventory, and radiotoxicity are obtained using a Monte Carlo method for nuclear data uncertainty propagation and the Monte Carlo transport code SERPENT. The impact of the nuclear data uncertainties for the two main actinide isotopes at the beginning of irradiation (235U and 238U) with the third and fourth most abundant actinide isotopes at the end of irradiation (236U and 239Pu) are calculated, showing the importance of fission yield data relative to transport data.