Coverage of exclusive breastfeeding (EBF) was targeted by Ministry of Health RI to reach 80%. The target is very difficult to achieve. Studies showed that EBF rate in Indonesia are very low. There are various factors affecting the success or failure of EBF. This study aims at digging information on predisposing, enabling, and reinforcing factors associated with success of EBF in Jagakarsa community health center, South Jakarta. Design of the study is qualitative with 14 informants that is mother with infant age >6-24 months and divided based on the success of EBF implementation. Data was collected through in-depth in-terview and was triangulated based on data sources including midwives and husbands as well as analysis triangulation by expert. Education, knowledge, and experience are predisposing factors that influence the success of EBF, while early breastfeeding initiation is a strong enabling factor, and support from mid-wife acts as a strong reinforcing factor. The study also found that advertisement of formulated milk was very successful in influencing mother’s success in EBF especially for those with low education. It is suggested to increase mother’s knowledge about EBF during antenatal care and not after the delivery. Legal aspect and rules should be implemented in a stricter way and to cover both mass-media advertisement and hidden campaign through health personnel.