The corrosion behavior of Fe55−xCr18Mo7B16C4Nbx (x=0, 3, and 4at.%) amorphous ribbons in Ringer's solution with pH value 6.5, open to air at 37°C, was investigated by linear polarization and electrochemical impedance spectroscopy (EIS) methods, aiming to estimate the feasibility of Fe-based metallic glasses as potential biomaterials. It was shown that the corrosion resistance in Ringer's solution significantly increases with an increase in Nb content. The linear polarization and EIS measurements indicated that the Fe51Cr18Mo7B16C4Nb4 possesses larger polarization resistance value than that of 316L stainless steel and Ti–6Al–4V which are used in the human body in biomedical applications. In addition, the ICP test was carried out to measure the concentrations of ions which had dissolved into the electrolyte. It was seen that amorphous alloys do not release any significant ions into the Ringer's solution, implying good biocompatibility of these alloys.