This paper proposes a new approach that enables a robust optimisation of the injection moulding process, based on the integration of numerical simulations, Response Surface Methodology and stochastic simulations in a type of integrated environment known as a virtual prototyping environment (VPE). The principal aim of the proposed approach is to include in the numerical setup of injection moulding the effects of fluctuations of process parameters. To clarify the proposed methodology, the paper details its application to the injection moulding process for the production of an engine cover. The moulded part presents some critical tolerances on different dimensions because of sealing and assembly requirements and the application of the VPE makes it possible to perform a robust setup taking into account the process fluctuations. The numerical prediction was confirmed by real production measurements on small pre-production runs performed adopting the moulding window explored in the virtual setup. (C) 2013 Elsevier Ltd. All rights reserved.