The effect of nanoclay additive on the structure, morphology, and mechanical properties of polypropylene meltblown webs is reported here for the first time. Effect of nanoclay on the meltblown processing, resultant fiber web structure, and properties are discussed. Combination of wide-angle x-ray diffraction, differential scanning calorimetry, and transmission electron microscopy were used to determine the nature of clay dispersion in the polypropylene fiber matrix and resultant morphology. Transmission electron microscopy micrographs revealed nanolevel dispersion of the additive in the fiber web. Clay additive did not offer any benefit as far as the mechanical properties of the meltblown web are concerned. Meltblown web samples with nanoclay had higher variability in web structure, high air permeability, high stiffness, and lower mechanical properties. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 1062-1072, 2010