This paper argues that decisionmakers need operational guidance about how to implement health policies in rapidly urbanizing developing contexts. Taking Bolivia’s Zero Malnutrition Program as a point of departure, the author conducted a comparative case study of health centers in three diverse cities, collecting data through participant observation, document review, focus groups and interviews. Findings highlight the unique issues urban-based health staff confront, including populations in transition, inequitable planning, and unmanageable workloads. Emerging strategies suggest that more progress could be made if health policy models like Zero Malnutrition’s accounted for such systemic constraints, while delegating more authority for localities to innovate.