Objective: To describe the experiences of breastfeeding mothers using the Unified Health System who were seeking to obtain knowledge, expectations, perceptions and feelings involved with identifying aspects relevant for more prolonged, exclusive breastfeeding Methods: A qualitative ethnographic study conducted with eight primiparas and family references, through observation and household interviews during the first semester of the infants' lives. The data were summarized in three categories: starting breastfeeding; experiencing the process of early weaning maintaining exclusive breastfeeding Results: Breastfeeding appeared as a particular event in different contexts of occurrence, however, it was possible to identify that exclusive breastfeeding was linked to maternal determination, despite the difficulties experienced. Longer Lasting exclusive breastfeeding was related to the mothers who were highly motivated to practice, those who were aware of its benefits and were supported by their family, even in the face of interference contrary to their culture. Conclusion: The lack of determination for exclusive maternal breastfeeding should be investigated and, when present, receive special consideration by health professionals.