Single stage injection blow moulding process, without preform storage and reheat, could be run on a standard injection moulding machine, with the aim of producing short series of specific blow moulded parts. Product launch time is lengthened by preform design time, which results in a far from optimal thickness profile of the blown product. In injection blow moulding, contrary to extrusion blow moulding, the polymer is not molten before blowing. As a matter of fact, the injection moulding step introduces a number of variable inputs in the blowing process, such as temperature gradients, strong molecular orientation and crystallisation onset. Therefore, mechanical, rheometrical and thermal properties of a polypropylene were measured. We used tensile testing results and oscillatory results to determine the parameters of different constitutive equations : a viscous Cross model, a viscoelastic K-BKZ model and a elastic plastic G'Sell model. Theses models were temperature dependent and used in finite element calculations with axisymmetric or three-dimension shell geometries. Comparisons between calculated and measured thickness were performed. The thickness was measured by a digital image processing technique developed in-house. Calculation highlights the importance of the initial temperature field and of the constitutive equation on the solution.