ln general, fiberboards are made of lignocellulosic fibers with synthetic adhesive to connect betweenfibers. Synthetic adhesives are usually non-biodegradable constituents and they cause health and envi-ronmental troubles. The present study aims to develop fiberboards from corn thermomechanical fibersreinforced with cellulose nanofibers. In this work, corn stalk biomass was used to produce high yieldthermomechanical 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 fiberboardswere characterized and compared with commercial high density fiberboard (HDF) containing syntheticadhesives. Fiberboards with 0.5 wt% CNF showed modulus of rupture of 43 MPa, similar to that of com-mercial HDF. The highest mechanical performance was reached for fiberboards at 2 wt% of CNF, withmodulus of rupture of 52 MPa. CNF was found to increase the resistance of the new all-lignocellulosicfiberboards when compared to the products made only with corn stalk fiber, and also when comparedwith commercial HDF.