Fe-based amorphous-nonocrystalline soft magnetic alloys with high magnetic permeability ( ? i ), low coercivity (Hc), high magnetic flux density (Bs), near-zero magnetostriction, and low core loss are in great demand for electromagnetic device applications, such as transformers, sensors, and electric motors. Recently, a new Fe-based nanocrystalline material, known as Nanomet (Fe–Si–B–P–Cu), with the high B S , and low cost has been attracted. However, these alloys have two limitations, their low glass forming ability (GFA) and the lack of plasticity, which restricted their engineering applications. One method to overcome these restrictions is the alloying of minor elements. The present study was aimed to investigate the effect of substitiution of Fe with varios alloying elements of Co, C, Mo, and Ni on the glass forming ability (GFA), nanocrystallization behavior, soft magnetc properties and mechanical properties of Nanomet alloy. Amorphous ribbons of Fe 83.3-x -(Si 4 B 8 P 4 Cu 0.7 )-M x (M=Co, C, Mo, Ni 0?x?8) alloys were synthesised by induction melting and melt spinning process. Microstructural characterization using X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermal behavior using differential scanning calorimetry (DSC) shows that distribution of pre-existing nuclei in the amorphous structure of Fe 83.3 Si 4 B 8 P 4 Cu 0.7 led to the anomalous crystallization, and hence, to a nonlinear Avrami plot with lowered localized Avrami exponents, and the significant increase in the coercivity (Hc) at low heating rates (?100°C/min). The presence of these nuclei was confirmed by non-zero magnetization in Curie point of Fe 83.3 Si 4 B 8 P 4 Cu 0.7 alloy in magneto-thermo-gravimetry (MTG) test. The determination of saturation magnetization (M S ) and coercivity (H C ) using vibrating sample magnetometer (VSM) and B-H looper, respectively shows that the optimum amount of varios alloying elements are 4 %at. Co, 1 %at. C, 1 %at. Mo and 4 %at. Ni. Then, with the simultaneous substitution of Fe with optimal amounts of Co, C, Mo, and Ni elements, CoCMo and CoCNi alloys were synthesized. The M S and H C were 176 Am 2 /kg and 20.8 A/m for CoCMo alloy, and 182.45 Am 2 /kg and 16.8 A/m, for CoCNi alloy after annealing at 450 °C for 5 min. The hardness and yYoung modulus obtaind by nanoindentation test showed that the substitiution of Fe with Co, C, Mo, and Ni decreased the hardness. The calculated thermodynamic parameters, P HS and P HSS , indicated that the addition of alloy elements, especially C and Mo elements improved the GFA and thermal stability of Nanomet alloy. As a result, the thickness of amorphous ribbons of CoCMo alloy increased by 33% in comparision with Nanomet alloy. With reduction of the rotational speed of melt spinner wheel from 3500 rpm to 1500 rpm, the M S improved duo to the surface crystallization and formation of ?-Fe crystalline phase, while the H C increased due to the magnetic anisotropy. This surface crystallization in amorphous structure decreased the harde of Nanomet and CoCMo alloys prepared at 1500 rpm.