Background The Baby-Friendly Hospital Initiative (BFHI) has been implemented by WHO and Unicef with a view to protect, promote and support breast feeding. This paper aims to assess the influence of the BFHI on breastfeeding indicators in Brazil, using data from the 2nd Survey of Breastfeeding Prevalence, conducted in 2008. Methods Data on 64 municipalities were analysed: a total of 65 936 infants under the age of 1 year who were covered by the 2008 immunisation campaign. The outcomes of interest were breast feeding in the first hour of life in infants under 1 year of age; exclusive breast feeding on the first day after hospital discharge in infants under 4 months of age; exclusive breast feeding in infants under 2, 3 and 6 months of age; and pacifier use in infants under 6 months of age. The influence of birth in baby-friendly hospitals (BFHs) on these end points was analysed by means of Poisson regression with robust variance for complex samples. Findings Infants born in BFHs were 9% more likely to be breast fed in the first hour of life and 6% more likely to be breast fed on the first day at home. Exclusive breast feeding was 13%, 8% and 6% more likely in infants under the ages of 2, 3 and 6 months, respectively, born in BFHs. Birth in a BFH also correlated with significant less pacifier use. Conclusions The BFHI has had an impact on several indicators of breast feeding. The authors hope the results of this study will make policy makers and health professionals aware of the importance and potential of this strategy. [ABSTRACT FROM AUTHOR]