In this paper, a 3D cellular automata approach of intergranular corrosion in presented. A model is proposed, along with experimental results both qualitatively (groove morphology, groove angle distribution) and quantitatively (mass loss, corrosion rate, corrosion front evolution). Simulations have been performed using a new asynchronous algorithm: the choice of the most adequate grid is also discussed. The model investigates the statistical variation of the corrosion front and provides useful information to make predictions on material ageing.