The spherulitic structure of isotactic polypropylene (iPP) from the melt was studied by polarized light and scanning electron microscopy. From the crystallization morphology, it can be observed that crystallization of iPP from the melt below 132 degrees C forms two types of spherulites, termed alpha- and beta-spherulites. The structure of iPP isothermally crystallized above 132 degrees C shows alpha-type only. The alpha-spherulites have a complex crosshatched array of radial and tangential lamellar structures, while beta-spherulites have, to some extent, simpler lamellar morphology with lower crosshatching content compared with alpha-type. However, in alpha-spherulites the radial lamellar thickness is greater than that of tangential lamellae, but in beta-spherulites the radial and tangential lamellae have approximately the same thickness.