The role of CaCO 3 nanoparticles as a reinforcing agent in increasing the mechanical properties of electrospun chitosan/poly(vinyl alcohol) (PVA) is inspired by the incorporation of CaCO 3 inside a chitin network in nature. The loading concentration of CaCO 3 nanoparticles varied from 1 to 5wt%, and the diameter of fibers ranges from 71.5±23.4nm to 140.7±15.1nm with an increased loading of CaCO 3 . A tensile test on 4wt% CaCO 3 -reinforced fibers revealed a Young’s modulus up to 912.5±60.6MPa from 15.7±3MPa, which is almost sixty times the value of fibers without CaCO 3 . The biocompatibilities of the CaCO 3 -loaded fibers were also tested in a 14-day simulated body fluid (SBF) incubation to induce the formation of apatite minerals and in a 14-day cell proliferation assay with ATDC5 cells. The chitosan/PVA–CaCO 3 (4wt%) was found to provide the most suitable environment for cell growth in comparison with chitosan/PVA and chitosan/PVA–apatite. The CaCO 3 -reinforced chitosan/PVA has potential to be a promising alternative as an artificial cartilage.