AbstractThis paper demonstrates the preparation of transparent biocomposites from chitin nanofiber using a series of simple mechanical treatments after the removal of proteins and minerals. Field emission scanning electron microscopy (FE-SEM) images show that the prepared chitin nanofibers are highly uniform with a width of less than 50 nm and a high aspect ratio. Due to the nano-size, the fibers are small enough to retain the transparency of the neat polymethylmethacrylate resin. Light transmission of the obtained chitin/PMMA biocomposite was 90.2%, in comparison to the neat resin, which was 92.6%. Mechanical property tests showed that chitin nanofibers significantly improved the tensile strengths and Young’s modulus of the neat PMMA, which increased from 43.8 MPa to 102 MPa and 1.6 GPa to 3.43 GPa, respectively. PMMA resin was found to be well dispersed in the biocomposite and had little effect on the tensile properties of the material. The properties mentioned above qualify the chitin nanofiber as a green and high-performance candidate having potential to be applied in next-generation optical electronic and building systems as a commercially available material.