Commercial grade isotactic polypropylene has been modified with a specific beta-nucleant (N,N'-dicyclohexylnaphthalene-2,6-dicarboxamide) in two concentrations (0.03 and 0.10 wt%). Specimens for structural characterization have been prepared by injection moulding, subsequent melting and re-crystallization or solid-state drawing at 100 T. Individual levels of hierarchical structure, including molecular orientation, have been characterized by a combination of wide angle X-ray scattering (WAXS), differential scanning calorimetry and scanning electron microscopy. Based on the analysis of the azimuthal reflections (110) and (300), the Hermans orientation functions have been calculated separately for the crystalline phases alpha and beta. Besides the longitudinal orientation along the injection-moulding direction, beta-crystallites tilted to the injection-moulding direction have been found. Upon thermal treatment the fraction of the crystalline beta-phase has decreased and molecular alignment within the crystalline regions has improved. During solid-state drawing the fraction of the crystalline beta-phase was markedly decreasing with increasing draw ratio, while the overall crystallinity has not changed but slightly. The experiments have also revealed a disruption of molecular alignment at the beginning of the drawing process and subsequent distinct improvement of molecular orientation along the draw direction in crystallites alpha and beta. The Hermans orientation functions provided by the WAXS analysis have been compared with recently published data obtained with similar specimens by polarized photoacoustic spectroscopy. (C) 2003 Elsevier Science Ltd. All rights reserved.