The frequency of oral yeast ingestion and its relationship with sucking and feeding habits was described in children from one to 18 months of age. Yeasts were detected in 58.3 percent of children and the most prevalent species were Candida parapsilosis and Candida albicans. The use of a pacifier was positively associated with the frequency of yeast infection and with the levels of these microorganisms in the mouth. No relationship was detected between the prevalence of yeast and breast-feeding or bottle-feeding habits. The results suggest that use of a pacifier is an important local factor in the colonization and proliferation of yeast in the oral cavity.