Pullulan (PULL)/montmorillonite clay (MMT) nanofiber blend mats with various weight ratios have been fabricated by the electrospinning technique in aqueous solution. The PULL/MMT nanofiber mats are characterized by X-ray diffraction (XRD), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and mechanical measurements. The study shows that the introduction of MMT results in improvement in tensile strength, and thermal stability of the PULL matrix. XRD patterns and TEM micrographs suggest the coexistence of intercalated MMT layers over the studied MMT contents. XRD analyses also reveal an increase of the crystallinity of the blend nanofiber mats with addition of MMT fillers. Moreover, FT-IR divulges that there might be possible interaction occurred between the MMT clay and PULL matrix. (C) 2009 Elsevier Ltd. All rights reserved.