OBJECTIVE: this study aimed to quantify the prevalence of breastfeeding in Brazil, macroregions, urban and rural areas, according to socioeconomic and demographic conditions. METHODS: the sample consisted of 2,958 Brazilian children from 0 to 1 year old. Data are from the Search Family Budgets, 2002-2003. Contingency tables, the chi-square test and trend test were used in order to verify the relationship between variables, significance was set at 5% and prevalence curves of breastfeeeding were made. RESULTS: the medians of brestfeeding (BF) duration were 8 months for the North region, 9 months for Northeast, Southeast, and South and 10 months for Midwest. In the group 0 to 6 months, the frequency of BF in Brazil was 58%. We found 63%, 59%, 51%, 61% and 56%, respectively, for North, Northeast, Southeast, South and the Midwest. In the rural area we found 60% and 58% in urban area. Mothers with higher incomes and more education had 60% and 65%, respectively. In the group 7 to 12 months the prevalence in Brazil was 35%. We found: 44%, 34%, 37%, 34%, 28%, respectively, for North, Northeast, Southeast, South and the Midwest. In the rural area we reported 39% and 34% for urban area. Mothers with lower incomes and less education had 38% and 40% of BF frequency, respectively. CONCLUSION: the greatest prevalence was found in North and Northeast region and the greatest median of BF was found in Midwest region. The BF patterns differed in two age groups. In the group 0-6 months, mothers with higher income and more education had higher frequency of BF. However, in the group of children from 7 to 12 months, the prevalence of BF was higher among mothers with lower income and less education.