Nylon 66/polypropylene (PP) blends containing maleated polypropylene and organo-montmorillonite (OMMT) have been prepared by melt compounding using a well-dispersed master-batch of nylon 6/OMMT nanocomposite as the source of OMMT. The effects of OMMT platelets on the compatibility and properties of the blends have been investigated. The blend morphology has been observed by the use of field emission scanning electron microscopy, showing a sharp decrease in domain size. The dispersion and location of OMMT have been investigated by X-ray diffraction and transmission electron microscopy. A high-density occupation of OMMT at the interface (i.e. Nylon-g-PP interphase region) is revealed by Fourier transform infrared spectroscopy and thermogravimetric analysis of the extraction residue after the removal of nylon phase by formic acid. A significant gain in stiffness is realized with the use of OMMT while the toughness of the material is maintained. The possible mechanism of compatibilization also is discussed. (C) 2009 Wiley Periodicals, Inc.J Appl Polym Sci 115:3697-3704, 2010