Aim: To evaluate the mother's perception of the oral health of their inpatient infants in maternity or infirmary units of a public hospital. Methods: Questionnaire applications were scheduled and educational lectures were carried out on how to sanitize the infant's mouth after breastfeeding, even in the absence of primary teeth, emphasizing the importance of breastfeeding. Results: A significant number of mothers reported that they received no guidance regarding the oral health care of their infants. They had never attended lectures by dental practitioners, as well as they did not know that the use of pacifier, baby bottle and digital sucking habit could interfere with their infant's oral heath over time. Conclusions: The majority declared that they had no care with the oral health of their infants. Only five mothers of newborns reported that they performed the oral hygiene of them once a day after the first breastfeeding. The mothers showed lack of knowledge on the diseases which can affect their children during early infancy as they had no information on how to prevent them. They did not know that early caries lesions could affect the infant and that harmful oral habits can predispose to the development of malocclusions.