A novel electrochemical biosensing platform is described using biocompatible, self-assembled ionic-complementary peptide nanofibers. The compatibility of a graphite electrode modified by these peptide nanofibers with enzymes is demonstrated using a model enzyme glucose oxidase (GOx). A glucose biosensor has been successfully fabricated by incorporating this enzyme into the modified electrode. From measurement of its electrode response and sensitivity, this nanofiber-modified electrode shows promise as an enzyme-based biosensor. The findings presented here demonstrate excellent potential of the use of ionic-complementary peptides to modify electrode surfaces for biomolecular sensing and diagnostics.