BackgroundDistrict Health Network (DHN), one of Iran’s most successful health reforms, was launched in 1985 to provide primary health care (PHC), in response to health inequities in Iran. The present study aims to use interrelated elements of the 3i framework: ideas (e.g., beliefs and values, culture, knowledge, research evidence and solutions), interests (e.g., civil servants, pressure groups, elected parties, academians and researchers, and policy entrepreneurs), and institutions (e.g., rules, precedents, and organizational, government structures, policy network, and policy legacies) to explain retrospectively how (DHN) policy in Iran, as a developing country, was initiated and formed.MethodsA historical narrative approach with a case study perspective was employed to focus on the formation and framing process of DHN. For this purpose, the 3i framework was used as a guideline for data analysis. This study mainly searched and extracted secondary sources, including online news, reports, books, dissertations, and published articles in the scientific databases. Primary interviews as a supplementary source were also carried out to meet cross-validation of the data. Data were analyzed using a deductive and inductive approach.ResultsAccording to the 3i framework, the following factors contributed to the formation of DHN policy in Iran: previous national efforts (for instance Rezaieh plan) and international events aiming to provide public health services for peripheral regions; dominant social discourses and values at the beginning of the Iranian revolution such as addressing the needs of disadvantaged and marginalized groups, which were embedded in the goals of DHN policy aiming to provide basic health services for deprived people especially living in rural and remote areas. Besides, the remarkable social cohesion and solidarity among people reinforced by the Iran-Iraq war were among other factors which contributed to the formation of participatory plans such as DHN (ideas). Main policy entrepreneurs including Minister of Health, his public health deputy and two planners of DHN with similar and rich background in the public health field and sharing the same beliefs (interests) which subsequently led to creation of tight-knit policy community network between them (institutions) also accelerated the creation of DHN in Iran to great extent. Political support of parliamentary representatives (interests), and formal laws such as principles of Iran Constitution (institutions) were also influential in passing the DHN in Iran.ConclusionsThe 3i framework constituents would be insightful in explaining the creation of public health policies. This framework showed that the alignment of laws, structures, and interests of the main actors of the policy with the dominant ideas and beliefs in the society, opened the opportunity to form DHN in Iran.