Laser surface alloying (LSA) of four different substrate alloys, including mild steel (G10500), austenitic stainless steel (S30400), aluminum alloy (A97075) and brass (C26000), with FeCrMoMnWCB powder (Nanosteel SHS717) was attempted. LSA was conducted in a two-step process: the powder was preplaced on the surface of the substrate by flame spraying and the pre-placed layer was subsequently remelted using a 2.5-kW CW Nd:YAG laser beam. The microstructures, sliding wear and corrosion behavior were studied by scanning electron microscopy, and X-ray diffractometry, pin-on-disc wear test and potentiodynamic polarization technique. For laser-alloyed G10500, S30400 and A97075, uniform alloyed layers were obtained by LSA but some cracks were found in laser-alloyed A97075. On the other hand, a non-uniform alloyed layer was observed on the surface of C26000 due to its high reflectivity and ball-up effect. For G10500 and S30400, the alloyed layers consisted of ferritic/austenitic iron-based matrix reinforced with the boro-carbides and their hardness increased to about 220 and 250 HV respectively. For A97075, the alloyed layer consisted of iron aluminides as the major phases and its hardness increased up to 450 HV. The sliding wear resistance of laser-alloyed S30400 and A97075 was higher than that of the substrates due to the presence of hard phases such as iron aluminide and boro-carbides, and solid solution hardened matrix. All of the laser-alloyed specimens showed no passivation in 3.5% NaCl solution at 23 °C. Except laser-alloyed C26000, the corrosion resistance of laser-alloyed G10500, S30400 and A97075 in 3.5% NaCl solution was deteriorated after LSA as evidenced by the increase in corrosion current density compared with the as-received specimens due to the existence of the phase boundaries of boro-carbides and iron aluminides as the active phases for corrosion attack. Among the laser-alloyed specimens, laser-alloyed S30400 possessed the highest wear and corrosion resistance.