New surface alloys were obtained on a low alloyed ferritic steel (Fe-0.38 C-5 Cr-1 Si-0.8 Mo-0.5 V) by laser processing after coating the surface with chromium carbide powder. Three different microstructures were observed depending on irradiation conditions : hypoeutectic, eutectic and hypereutectic, all containing iron solid solutions (austenite and martensite) and iron-chromium carbides (Fe, Cr)(7)C-3. The oxidation resistance of these alloys was measured in isothermal and cyclic conditions, and was shown to increase with chromium concentration. The hypereutectic alloy, containing 35% Cr, was particularly resistant due to the formation of a chromia scale with excellent behaviour during thermal shocks.