In this study the electrospinning of polyvinyl alcohol (PVA) was evaluated and optimized for minimum fiber diameter following Taguchi methodology. The effect of four factors including the solution concentration, voltage, flow rate and needle- collector distance each at 3 levels on fiber diameter were investigated. The morphology and the diameter of the fibers were studied by a scanning electron microscope. It was found out from the main effects and the analysis of variance that in the range of levels studied concentration is the most influencing factor on the fiber diameter with a contribution of 89.22%. Voltage makes a minor contribution of 10.028% and the flow rate and distance have negligible influence (less than < 1%). The minimum fiber diameter was predicted to be 381 nm and to be achieved at the combination of concentration of 8 wt.% PVA, voltage of 18 kV, flow rate of 0.7 cm(3)/h and the distance of 10 cm. Validation experiment resulted in fibers with 390 nm diameter which is in close agreement with the predicted value by the Taguchi technique.