The objective of this paper was to analyze the determinants of smallholder milk production expansion in four Brazilian regions: Zona da Mata (MG), Rio de Janeiro, Tocantins, and Rondônia. A three years multi-period linear programming model was formulated to attain the objective purposed. The results show that smallholders can improve substantially their income with the adoption of low cost technologies, such as improvement in feeding and reproduction practices. The role of the public sector is important in this process of adoption of new technologies, especially providing accessible veterinary and extension services, and soft loans.