Milk production is an important component of farming systems in the Brazilian Amazon agricultural frontiers, Developed mainly by smallholders, this activity appears as a promising alternative to improve sustainability of these regions development. More than on technological constraints, long-term sustainable smallholders milk production depends on the emergence of a local production and marketing milk chain. A comparative analysis of three contrasted regions in the Eastern Brazilian Amazon allows to underline the main determinants of such a chain development and to suggest some policies and support actions, which may favor sustainable milk production development.