The metallic glass ribbons of [(Fe_xCo_1-x)_0.75B_0.2Si_0.05]₉₆Mo₄ (x = 0, 0.3, 0.6, 0.9 at.%) and [(Fe_xCo_1-x)_0.75B_0.2Si_0.05]₉₆Nb₄ (x = 0, 0.3, 0.6, 0.9 at.%) were obtained by melt spinning with 25-30 μm thickness. The thermal stability, mechanical properties and magnetic properties of Fe-Co-B-Si based systems were investigated. The values of thermal stability were measured using differential scanning calorimetry (DSC), including glass transition temperature (T_g), crystallization temperature (T_x) and supercooled liquid region (ΔT_x=T_x–T_g). These amorphous ribbons were identified as fully amorphous, using X-ray diffraction (XRD). The mechanical properties of Febased samples were measured by nano-indentation. Magnetic properties of the amorphous ribbons were measured by a vibrating sample magnetometer (VSM). The amorphous ribbons of [(Fe_xCo_1-x)_0.75B_0.2Si_0.05]₉₆Mo₄  (x = 0, 0.3, 0.6, 0.9 at.%) and [(Fe_xCo_1-x)_0.75B_0.2Si_0.05]₉₆Nb₄ (x = 0, 0.3, 0.6, 0.9 at.%) exhibited soft magnetic properties with low coercive force (H_c) and high saturation magnetization (Ms).