Taking into account advantagous properties of nanofibers in tissue engineering, fibrous biocomposites scaffolds of poly(vinyl alcohol) (PVA), nanohydroxy apatite (nHAp) and cellulose nanofibers(CNF) electrospun and characterized. Scanning electron microscopy (SEM) and filed emission SEM (FE-SEM) were applied to investigate morphology of spun fibers. The 8 wt.% PVA solution at 15 cm electrospinning distance resulted in bead-free fibers with 238±38 nm average diameter. Loading 1 to 15 wt.% nHAp into PVA solution, it was shown that at 10 wt.% of nanoparticles, fibrous scaffolds with appropriate mechanical and morphological properties were obtained. Then, different amounts of CNF were loaded into PVA/nHAp10. By increasing nHAp and also CNF average diameter of fibers decreased to lower than 150 nm. Both nanofillers corporation and probable interactions caused emergence of new peaks and also change in position available peak in ATR-FTIR patterns, respectively. Thermal behaviour analysis proved that electrospinning and filler addition led to increase in glass transition temperature (T g ) and crystalline temperature (T c ), but reduction ofmelting point (T m ). Wide angle x-ray scattering (WAXS) was applied to study supermolecular structure of electrospun fibers. PVA powder WAXS pattern displayed four distinct crystalline peak, however, electrospinning and filler addition left only one broad peak at 19.3°, which are evidences for PVA crstallinity reduction. In the case of electrospinning, this effect is observed due to extremely short time of solvent evaporation during the process resulting in stopping of crystallization at the early stage. In the case of additives, the mechanism of PVA crystallinity reduction is most probably due to the interactions between –OH groups in matrix (PVA) and nanofillers as well as calcium ions in nHAp. Tensile mechanical characterization of fibrous scaffolds was carried out. it was obtained that PVA/nHAp at 10 wt.% nanoparticles (PVA8/nHAp10) had the highest tensile modulus (142.84±7.10 MPa). Adding 3 wt.% of CNF to this sample resulted in a 3-component composite scaffold (PVA8/nHAp10/CNF3) with 322.90±20.47 MPa modulus. Heat treatment of scaffolds at 180 o C made them stable against water disintegration. Hydrophilicity of scaffolds was investigated by contact angle method which was determined that PVA composite fibers were more hydrophil than pure PVA fibers. In addition, biodegradability in demonstrated that nanofillers (nHAp and CNF) reduced degradation rate of scaffolds. Biomineralization in SBF also was done which showed higher mineralization of composite scaffolds, compared to pure PVA scaffold. MTT assay proved that both nHAp and CNF decreased cytotoxicity of PVA scaffold. Furthermore, cell attachment, characterized by SEM, and functionality, investigated by alkaline phosphatase (ALP) and alizarin red, proved that nanocomposite scaffolds had higher potential in MG-63 osteoblast growth, proliferation and osteogenic activity. Another aim of current study was to investigate the mechanical properties of electrospun PVA and its nanocomposites. Tensile test and AFM nanoindentaion were applied to measure tensile modulus of elecrospun scaffolds and electrospun single fibers, respectively. In addition, theoretical models were used to predict stiffness of nanocomposites and verify their accuracy by experimental data. In conclusion, Generally, the obtained results confirm that the 3-component fibrous scaffold of PVA/nHAp/CNF has promising potential in hard tissue engineering. Keywords: Poly (vinyl alcohol), Biocomposite, Electrospinning, Electrospun scaffold, Bone tissue engineering