Yeasts present in the sourdough that is generally used for the production of durum wheat bran flour bread wereisolated and identified. Samples were taken during the rebuilding phase and at different intervals of time in order to monitor the population dynamics. The results obtained from the phenotypic studies were further confirmed by the molecular studies and enabled us to affirm that most of the strains, more than 95%, belong to the species Candida humilis. The dominance of C. humilis was steady in time. The isolations were carried out at sufficiently long intervals so that it was possible to ascertain that the conditions in which the sourdough is kept are fundamental to the microbiological stability of the dough.