Birth and death stochastic processes are confirmed to operate in pitting corrosion of ferritic stainless steels containing Cr, Mo, Ti and Nb. Birth process corresponds to pit generation and death process to pit repassivation, each rate being determined as a function of potential by the analysis of survival probability vs. time curves based on the stochastic theory. Pitting potential is found to shift to the noble value with the addition of all the alloying elements examined. The cause of the shift, however, differs for each element. The shift by alloying Cr, Ti and Nb is caused by a decrease in the pit generation rate, while the pit repassivation rate remains constant. In contrast, the addition of Mo enhances the rate of repassivation and decreases the pit generation rate. These changes of both rates are contributing to the observed shift in pitting potential to the noble value.