The crystalline morphology of a relatively high molecular weight isotactic polypropylene (i-PP) (M(w) = 18000 g/mol) with well-defined regio- and stereoirregularities is studied by means of atomic force microscopy (AFM), wide-angle X-ray scattering (WAXS), small-angle X-ray scattering (SAXS), and light microscopy. This i-PP crystallizes under certain crystallization conditions nearly exclusively in the gamma-modification. The growth of the gamma-phase is often influenced by the initial growth of the alpha-phase, but also the neat gamma-phase is observable. The formation of the gamma-phase can be related to stereo- and regioirregularities in the polymer chain caused by the polymerization mechanism using metallocene catalysts. WAXS measurements show that at large supercoolings the formation of alpha-phase i-PP is preferred, whereas at low supercoolings this sample crystallizes nearly exclusively in the gamma-modification. Light microscopy and AFM reveal for the gamma-phase i-PP morphologies different from the well-known spherulites formed by the alpha- or beta-modification. However, it can be shown that the morphology development of gamma-phase i-PP can be widely influenced by very small amounts of alpha-phase i-PP. A lamella thickness of about 4 nm and a long period of 12 nm of gamma-phase i-PP isothermally crystallized at 100 degrees C are obtained from SAXS measurements. At very low supercoolings, supermolecular structures of the neat gamma-modification are formed in competition with mixed (alpha and gamma) morphologies. In thin films the neat gamma-modification shows network structures, which are formed by triangular entities. Etched bulk samples reveal columns with a rectangular cross-section which are densely packed. On the molecular scale, the surface topography of the flat-on extended chain lamellae with periodic distances of rows of methyl groups of 3.6 Angstrom is measured. This value is in excellent agreement with the distance of the methyl group rows on the crystallographic (010) plane according to the nonparallel chain packing model by Bruckner and Meille.