Exclusive breastfeeding, one of the best natural resources, needs protection and promotion. The International Code of Marketing of Breast-milk Substitutes (the Code), which aims to prevent the undermining of breastfeeding by formula advertising, faces implementation challenges. We reviewed frequently overlooked challenges and obstacles that the Code is facing worldwide, but particularly in Southeast Asia. Drawing lessons from various countries where we work, and following the example of successful public health interventions, we discussed legislation, enforcement, and experiences that are needed to successfully implement the Code. Successful holistic approaches that have strengthened the Code need to be scaled up. Community-based actions and peer-to-peer promotions have proved successful. Legislation without stringent enforcement and sufficient penalties is ineffective. The public needs education about the benefits and ways and means to support breastfeeding. It is crucial to combine strong political commitment and leadership with strict national regulations, definitions, and enforcement. National breastfeeding committees, with the authority to improve regulations, investigate violations, and enforce the laws, must be established. Systematic monitoring and reporting are needed to identify companies, individuals, intermediaries, and practices that infringe on the Code. Penalizing violators is crucial. Managers of multinational companies must be held accountable for international violations, and international legislative enforcement needs to be established. Further measures should include improved regulations to protect the breastfeeding mother: large-scale education campaigns; strong penalties for Code violators; exclusion of the formula industry from nutrition, education, and policy roles; supportive legal networks; and independent research of interventions supporting breastfeeding.