The radio source 3C 265, located at z = 0.811, is one of the most luminous radio galaxies in the 3CR catalogue. Indirect evidence for the presence of a powerful quasar in the nucleus of 3C 265 was provided by optical, infrared, and radio studies. We present preliminary results from new Chandra X-ray observations of the radio galaxy 3C 265, allowing us to test the presence of such a powerful quasar, and at the same time to study the effect of the intense nuclear flux on the relativistic electron population in the radio lobes of 3C 265. (C) 2003 Elsevier B.V. All rights reserved.