The objective was to investigate the Community Health Agents (CHA) knowledge in breastfeeding. An analytical cross-sectional study with ACS of both genders that work in the Family Health Strategy. The data were obtained through a questionnaire, including open and closed questions regarding their socioeconomic, professional and breastfeeding knowledge. A total of 116 ACS patients with an average age of 44.2 ± 8.8 years and 14.7 ± 5.2 years of service time participated. Of these, 69.6% reported having performed some training, and only 24.8% and 6.2% obtained a satisfactory knowledge classification, related to important aspects about the technique and management of intercurrences in breastfeeding, respectively. Regarding the answers of the closed questions, which were about general knowledge about breastfeeding, the average number of correct answers was 15.2 ± 3.2 questions, which was significantly higher (p = 0.019) among professionals working in the urban area in Rural areas. In view of the results, there is a need for greater investments in the training of the ACS in breastfeeding, so that they can acquire the necessary knowledge to effectively work with pregnant women and nursing mothers, especially with regard to adequate breastfeeding techniques and treatment of breast complications.