The surfaces of the amorphous metal-metalloid alloy Fe80B20, prepared by melt-spinning and by picosecond pulsed laser annealing, respectively, have been investigated by STM, XPS and AES. The results show that the as-quenched (by melt-spinning) surfaces consist of a non-periodic surface structure comprised of basic structural units ≈ 5 nm in size; these features are absent after laser annealing. The native oxide layers on both surfaces were found to be fully dense with a thickness of ≈ 1 nm. The effect of laser annealing was to producea large enhancement of the boron concentration in the first 0.5-1 nm of the surface and to promote the surface oxidation of boron and iron. The results have been interpreted in the context of the known effects of pulsed laser annealing on the thermal stability of this alloy. © 1990.