Solid phase nitriding of titanium by CO2 laser was carried out in order to investigate the growth of the nitrided layers under CO2 laser irradiation. Results show that the major characteristics are only related to the particular thermal cycles induced by the laser irradiation. Direct irradiation of the substrate does not produce any specific assisted nitride growth. Moreover, in the case of titanium nitriding, no significant evolution of the CO2 laser-surface coupling results from the superficial nitrided layer growth.