© 2019 This work presents a model capable of describing the influence of the crystallographic texture and microstructure produced by Voronoi tessellation on the initial stage of pitting corrosion in API 5L steels. The proposed model takes into account several physical parameters of the material such as crystallographic orientation, gran size, grain boundary, number of inclusions, surface energy, and the Gibbs free energy change. The number of corrosion pits and their distribution associated with the initiation of pitting corrosion were determined using both Monte Carlo simulation and corrosion test. The good agreement between simulation results and the experimental observations verified the validity of the proposed model. The results showed that the pits initiation depends strongly on the change of surface energy due to the formation of new phases and the character of grain boundary and its distribution. The behaviour of nucleated pits is completely random, while their subsequent growth from a nucleation site has a strong influence from the crystallographic grains orientation.