OBJECTIVE To compare the prevalence rates of breastfeeding and the principal causes of consultations at the infant and neonatal clinic of a basic healthcare center in the city of Rio de Janeiro, before and after its being accredited by the Breastfeeding Friendly Primary Care Initiative. METHODS Information was analyzed from 121 and 200 children followed-up at the healthcare center before and after certification, respectively. Type of feeding was classified as exclusive breastfeeding, predominant breastfeeding or breastfeeding, and the 10th International Classification of Diseases was used to classify the complaints causing consultations. RESULTS A statistically significant increase was observed in the prevalence of exclusive breastfeeding, both among those less than 4 months old (68 vs. 88%; p < 0.0001) and among children aged from 4 to 6 months (41 vs. 82%; p < 0.0001). Furthermore, an impressive increase was observed in the prevalence of breastfeeding in children more than 6 months old, especially those aged 9 to 12 months (24 vs. 82%; p < 0.0001). After certification, there was also a reduction in the number of consultations motivated by some type of disease among infants more than 4 months old. CONCLUSION Implementation of the Breastfeeding Friendly Primary Care Initiative proved to be an important strategy for increasing the rate of breastfeeding and reducing consultations due to disease among infants less than one year old cared for at this health center.