The objective of this investigation has been the study of corrosion resistance of Fe 2.5 Co 64.5 Cr 3Si 15 B15 , Fe 3Co 67 Cr 3Si 15 B12 and Fe 5Co 70 Si 15 B10 amorphous metallic alloys obtained by the melt spinning technique, used as based materials to create a new type of giant magnetoimpedance (GMI) biosensor. The corrosion behaviour has been studied in phosphate buffered saline (PBS) solutions at pH 7.3 and 37.5 oC. The electrochemical characterization of alloys has been made by means of DC techniques, obtaining the corrosion potential, pitting and protection potentials, as well as the perfect and imperfect passive regions of alloys. In this work, the experimental results obtained are discussed in order to study their corrosion behaviour in artificial biological solutions and thus determine their possible use as GMI-biosensor prototype materials.