Stator vanes which are found in axial compressors are subject to vibratory fatigue. Their division into monoblock sectors makes the prediction of their vibratory behaviour difficult by deterministic methods due to the loss of the cyclic symmetry properties and also to a high sensitivity to mistuning. The purpose is to present a robust calculation strategy based on a stochastic modelisation of the structure. The methodology has been developed first on a simplified model and then applied to an industrial case. Polynomial chaos based results are in good agreement with reference Monte Carlo simulations.