The surface properties of amorphous and crystalline polyester films, well below their glass transition temperature, have been studied with an atomic force microscope. For amorphous films a corrugated pattern develops on the surface as a result of scanning and the corrugations are always perpendicular to the scan direction. When scanning is stopped the pattern shows a slight relaxation; however, the surface is plastically deformed. When crystalline films are scanned, similar patterns are seen which are less pronounced and require a much longer scan time. These results suggest that the physical properties of a glassy polyester surface may be different from the bulk, and the freedom of macromolecules is reduced upon crystallization, thus suppressing molecular motion at the surface.