A poly(acrylonitrile) (PAN) nano-web was electrospun on a commercial melt-blown poly(propylene) (PP) filter medium to generate composite filter media. The performance of these media was characterized in terms of filtration efficiency and pressure drop. Quality factors calculated from these parameters were used to evaluate the overall efficacy of the filter media. Structural characterization of the composite media showed that a thin layer of nano-web could improve the overall performance by increasing filtration efficiency without significant increase of pressure drop.