in general, fiberboards are made of lignocellulosic fibers with synthetic adhesive to connect between fibers. Synthetic adhesives are usually non-biodegradable constituents and they cause health and environmental troubles. The present study aims to develop fiberboards from corn thermomechanical fibers reinforced with cellulose nanofibers. In this work, corn stalk biomass was used to produce high yield thermomechanical pulp (TMP) that was converted into binderless fiberboards. Cellulose nanofibers (CNF) were also added as reinforcing agent. The mechanical and physical properties of the resulting fiberboards were characterized and compared with commercial high density fiberboard (HDF) containing synthetic adhesives. Fiberboards with 0.5 wt% CNF showed modulus of rupture of 43 MPa, similar to that of commercial HDF. The highest mechanical performance was reached for fiberboards at 2 wt% of CNF, with modulus of rupture of 52 MPa. CNF was found to increase the resistance of the new all-lignocellulosic fiberboards when compared to the products made only with corn stalk fiber, and also when compared with commercial HDF.