The present study focused on an investigation of significant electrospinning parameters on Mg-doped fluorapatite nanoparticles-poly (ε-caprolactone) fibrous nanocomposite scaffold (Mg-FA NPs/PCL). Since there are many factors that could have an influence on electrospinning process, Taguchi experimental design approach was used to reduce the number of experiments. The selected parameters included the concentration of polymer, solvent system, ceramic concentration, applied voltage, and the distance between nozzle and collector. The analysis of variance (ANOVA) showed that, among the studied parameters, polymer concentration and type of solvent had the most significant effect on the consistency of the solution which played a major role in producing uniform non-beaded fibers. In order to maximize performance of electrospun scaffold, the surface tension should be kept minimizing by decreasing concentration, applying a high dielectric solvent system, increasing voltage, and declining distance in a very stable electrical field. Eventually, the optimum condition to fabricate Mg-FA NPs/PCL fibrous scaffold was electrospinning 10 wt% PCL with 1 wt% Mg-FA NPs solution in chloroform by applying 20 kV into 20 cm distance. According to the bioactivity and cell attachment results, the electrospun Mg-FA NPs/PCL is suggested as a promising candidate for tissue engineering, especially for bone tissue. K E Y W O R D S biological properties, electrospinning parameters, nanoparticles, Taguchi method, tissue engineering 1 | INTRODUCTION Recently, electrospinning has been applied as an appropriate and effective technique to produce biomimetic nanofibrous scaffolds consisting of a vast web of interconnected fibers and pores. 1-4 The structure of bone extracellular matrix (ECM) includes a fibrous collagen with homogeneously dispersed hydroxyapatite (HA) nanocrystals, therefore, applying electrospun scaffolds for bone tissue engineering has interestingly been increased. A numerous polymers have been employed to engineer the ECM tissues including either as natural polymers such as collagen, gelatin, chitosanor as synthetic polymers for example poly (lactic acid) (PLA), poly (lactide-co-glycolide) (PLGA), poly (glycolic acid) (PGA), polyurethane (PU), poly (ethylene glycol) diacrylate (PEGDA), and poly (ε-caprolactone) (PCL). 1-3,5-9 Owing to the appropriate mechanical properties and controllable degradation rate of synthetic polymers, researchers are extensively interested in