The laser surface alloying of 18/8 stainless steel with Mn, was carried out by 6 kW cw CO2 laser. The microstructure, chemical composition and phase identification of the modified layer were examined using scanning electron microscopy, energy dispersive X-ray spectroscopy and Xray diffractometry, respectively. Cavitation behavior of produced layers was investigated in a rotating disc facility. Cavitation properties of laser-processed steel were calculated in the initial stage of erosion, on the surface of about 4 mm2, on which cavitation intensity was constant. As a property characterizing the cavitation erosion resistance of materials was proposed for the depth of strain hardening. It was found that presence of manganese in the amount of 7.31% causes the highest increase hardness after alloying and the lowest depth of strain hardening due to cavitation loading.