The present work focuses on the effects of thermomechanical history on the structure and mechanical behaviour of PVDF. In the first part of our investigation differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) are used to follow the evolution of the structure of PVDF after different annealing treatments or deformation. Processing has a significant impact on the quantities of the amorphous and crystalline phases and their interphase. Subsequent annealing affects these phases in a different proportion. This influence depends on the position of the annealing temperature in comparison with the upper glass transition temperature of PVDF. Deformation induces conformational change in the injection moulded samples. Thus, the or conformation is transformed to the P conformation. The P conformation also has a noticeable influence on the mechanical behaviour of the material, which will he discussed in the second part of our study.