Abstract. A theoretical description of the magnetic properties in disordered alloys Fe-M (M=AI, Si, Sn, Ga) on the basis of a two-band model of the Hubbard type is presented. It is shown that at T=O the local magnetic moment is determined by the number of metalloid atoms in the nearest environment and weakly depends on the concentration, which allows to use the Jaccarino-Walker model for the description of the experimental results. The thermodynamical Stoner excitations have essential effect at high concentration of the metalloid. The spin density fluctuations should be taken into account in a calculation of the concentration dependence of the Curie temperature at low concentration. So, at all concentrations, the itinerant character of the magnetism of these alloys does not allow to use localized models.For a long time the disordered alloys of metal-metalloid type (Fe -Al, Fe -Si, Fe -P, Fe -Sn) have been attracting the attention of scientists. This interest is mainly due to the fact that these alloys have a wide concentration range for the homogeneous disordered state and this constancy of structure makes them a good model object for studying the magnetism in disordered systems. The successful interpretation of the experimental results by the modified Jaccarino-Walker (J -W) models gives the grounds for the usage of these models [1,2]. However, the J -W models are conceptually closer to the localized models whereas magnetism in iron is of itinerant character. In the alloys, the magnetism has even more collectivized character, which follows from the increase in the Rhodes-Wohlfarth parameter (RW) with concentration (this parameter is the relation of the magnetic moment, found from the Curie constant, divided by the saturation 375 D. Wagner et al. (eds.), Itinerant Electron Magnetism: Fluctuation Effects,[375][376][377][378][379][380][381][382][383][384][385][386][387][388][389]