This paper reports the study of the changes in the surface properties of thin chromium film (ca. 600 nm) after implantation with nitrogen ions. The chromium film was deposited on silicon substrates using electron beam evaporation. Doses in the range of 10(17)-10(18) N+/cm(2) and energy of 15 keV were carried out, in order to investigate the hardness and roughness modifications due to implantation. After annealing the samples at 500 degreesC under vacuum conditions, the nitrogen distribution for different doses was analyzed using secondary ion-mass spectrometry. By means of X-ray diffractometry the phase composition was characterized and lattice parameters were calculated. Atomic force microscopy was used to evaluate and compare the surface roughness before and after implantation. (C) 2004 Elsevier B.V. All rights reserved.