Organo-modified aluminophosphate with kanemite-like structure was used for the in situ synthesis of polypropylene (PP) nanocomposites performed by metallocene-catalyzed polymerization. The filler exhibits a layered structure with different organic pending groups arranged in the interlayer space. Melt-compounded composites with the same filler were prepared for comparison.X-ray diffraction (XRD) and transmission electron microscopy (TEM) proved exfoliation of the filler in the PP matrix and formation of nanocomposite after in situ synthesis. In contrast, in the melt-composites the filler is agglomerated and only microcomposites are obtained. (C) 2014 Elseviet Ltd. All rights reserved.