Conflict of interest: non-existent diarrhea, malnutrition, respiratory infections, miofunctional orofacial disorders and decreases the risk of allergies, hypertension, high cholesterol rate, diabetes and obesity [1][2][3] .Breastfeeding is a perfect bound between a mother and her child, fulfilling a function of an external "umbilical cord". A breastfeeding woman sees comforted their ability to continue to generate life through the food that she offers 1 . In addition, mothers who breastfeed have a lower chance of developing breast cancer in the future. Breastfeeding may also act as an adjunct in the prevention of a new pregnancy, it has low financial cost, provides satisfaction, and, in advance, creates a motherbaby bound.Currently is recommended exclusive breastfeeding for six months, and maintaining breastfeeding supplemented by two years or more 5 . Despite abundant scientific evidence regarding ABSTRACT Purpose: to determine the influence of received guidance about breastfeeding on the knowledge and practices of mothers attending a university hospital. Methods: descriptive observational study conducted with 250 mothers, aged between 18 and 45 years, who were in the Phonoaudiology Clinic for conducting newborn hearing screening and had their babies no later than six months ago. These mothers, who were previously oriented or not, answered a questionnaire about breastfeeding. Results: mothers who received previous guidance showed greater knowledge about: the appropriate age to offer other foods (p = 0.001), the utensils used for food (p = 0.031), the disadvantage of bottlefeeding (p = 0.037) and pacifier (p = 0.019). Only mothers guided both on pre and post-natal reported using a syringe for feeding (p = 0.045). Moreover, the percentage of mothers who breastfeed on demand and new how to store milk was higher among those who had received guidance on the subject (p <0.001 and p = 0.027). The preparation of the breasts was best performed by mothers not previously guided (p = 0.002). Conclusion: this study showed that receiving guidance on breastfeeding did not determine greater knowledge on the subject, emphasizing the need of having a multidisciplinary team working in guidance of mothers as well as the importance of participation of the phonoaudiologist, who is the qualified professional to address issues of prevention of orofacial disorders.