Surface treatments, surface modification and surface engineering are required to improve the wear resistance, erosion resistance, friction resistance and corrosion protection. Transformation hardening of metals has been used since ancient times to increase the hardness and thereby vastly reduce the wear rate of metal surfaces in use. Today several processes are in use to achieve the controlled heating and rapid cooling required for transformation process. Transformation hardening is one of the most attractive processes for high power diode lasers, since their moderate beam quality and their low power density is sufficient for many applications. Generally laser hardening generates less distortion than conventional methods. In this study, the effect of laser beam characteristics (beam profile, power density, power etc) was examined on the micro hardening of carbon steel.