${(Fe_{0.85}Co_{0.15})}_{75}Al_{7}B_{18-x}Nb_{x}(x=2,;4;and;6;at%);and;{(Fe_{0.85}Co_{0.15})}_{75}Al_{y}B_{21-y}Nb_{4}(y=3,;5,;7,;9;at%)$ alloys were prepared by a single-roll quenching method. Microstructure and magnetic properties of the alloys such as saturation magnetization, initial permeability, coercive force and power loss have been investigated as functions of composition and armea1ing temperature. Nanocrystallines are obtained by armealing of as-prepared amorphous alloys in all compositions except the alloy of 9 at% AI. Saturation magnetization increases after armea1ing and, decreases with Nb content. However, AI and B affects the saturation magnetization insignificantly. Initial perrreability of nanocrystallized alloy at 50 kHz is improved roore than twice compared to that of the as-prepared alloy. Coercive force and core loss reach less than half after armea1ing.