Polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP)/acetone solutions were electrostatically spun into sub-micron fibers at various conditions. The variables chosen were polymer concentration, applied voltage, flow rate, and tip to collector distance (TCD). The average fiber diameter increased with an increase in the polymer concentration, however, the trend for applied voltage was not monotonous showing minimum diameter of 0.8㎛ at 15.6 kV. The fiber diameter was also depended on TCD; the minimum fiber diameter at 15 cm. The flow rate of the solution was another factor; lower the flow rate, finer the fiber diameter. The PVDF-HFP web was also treated for air filter application i.e., water contact angle and air permeability. Though the web was consiting of ultra-fine fibers, the contact angle with water was still high as 157˚ representing high hydrophobicity. The web showed high air permeability of 12.69 cc/㎠. sec, and the value decreased with increase in thickness of the web.