The locations of the stacking faults in p-form single crystals of syndiotactic polystyrene, which were grown isothermally from a dilute solution at temperatures ranging from 150 to 210 degrees C, were identified in high-resolution and dark-field (DF) images taken by transmission electron. microscopy, The shift or kink of the (210) lattice fringes, which shows the position of the fault, was directly detected in the high-resolution images. DF images taken using several reflections exhibited irregularly spaced striations parallel to the b-axis. Computer simulation of DF images based on the structural model of the stacking fault well supported the view that each striation corresponds to the position of the fault. The striations extended continuously and were very long, and accordingly, it was proposed that the stacking fault influences the attachment of a new polymer stem onto the lateral growth face which is not parallel to the be-plane, resulting in irregular fold-surfaces of the single crystals.