In the present work, chitosan (CS) nanofibers were mineralized in order to enhance their osteoconductivity and the calcium phosphate (CaP) compounds formed on the surface were characterized. CS nanofibers blended with CS and polyvinyl alcohol were fabricated using an electrospinning technique. These fibers were soaked in a modified simulated body fluid (m-SBF) to encourage the formation of CaP for 1-7days. Sphere-like CaP crystallites with average diameter of 350nm were evenly formed on the surface of CS nanofibers. Their density increased with increasing soaking time in m-SBF. These crystallites were aggregated with the nano-sized crystallites which had plate-like shape and low crystallinity. High-resolution transmittance electron microscope image showed that these crystallites of CaP had -tricalcium phosphate crystalline structure which had higher solubility compared with octacalcium phosphate or hydroxyapatite. The mineralized CaP/CS nanocomposite fibers in m-SBF could be promising biodegradable scaffolds for bone tissue regeneration.