Though chemically simple, polyethylene has proven to be an extremely versatile polymer. Its physical and mechanical properties can be made to cover a broad range of requirements by varying processing, branching, and the molecular weight of the material. In particular, ultrahigh modulus polyethylene (tensile moduli exceeding 200 Gpa) has been made by solid state extrusion (SSE) at 110 C followed by post drawing (PD) at 125 C. The objective of the following study was to investigate the evolution of structure during the SSE/PD process, and to identify those morphological features which give rise to ultimate properties.The SSE/PD process was mimicked here by deforming thin films of HDPE at high temperature (129 C). High density polyethylene (HDPE) of Mw = 200,000 and Mw /Mn =7-13 was used. As-processed films were highly oriented and displayed a single crystal-like textured shish-kebab morphology.