The 3CRR sample of radio galaxies and quasars has been cross-correlated with the ROSAT PSPC All-Sky Survey. About 25 per cent of the objects have been detected in the 0.2-2.4 keV range, the large majority being powerful radio and X-ray emitters with a range of X-ray luminosities between 10^44 and 10^46 erg s^-1. The 0.2-2.4 keV spectrum of the radio-loud sources is found to be well characterized by a single power-law continuum absorbed by typical Galactic H column densities. The range of power-law spectral indices (-1.5