The multiphase structure of thermoplastic polyurethane elastomers is not only influenced by the chemical structure, but also by the processing conditions. The polymorphism of hard segment (HS) crystallites of a commercial polyurethane was investigated in dependence on the melt processing conditions using WAXS and d.s.c. The observed crystalline morphology types are strongly influenced by the processing temperature. Analysis of the results permits the assignment of HS crystallites of so-called ＇type II＇ with high WAXS intensity to those melting above 220 degrees C. Additionally, the tensile strength was determined. These results related to the d.s.c. data allow to establish a processing-structure-property elation.