The aim of this study was to determine the socioeconomic, production characteristics and milk production cost of dual-purpose farms (DPF) oriented to milk production in a subtropical region of Central Mexico. The study focused on ten DPF that produce milk all year round, to gather socioeconomic characteristics of farmers (age, family structure, education level), farm resources (land holding, herd structure, infrastructure, management) and economic information during the year 2008. Family labour (FL) covers 66% of labour needs. The average milk production cost was US$0.21, fluctuating from US$0.19 to US$0.31 during the rainy and dry season, respectively. Supplements and hired labour (HL) accounted for 48 and 35% of milk production cost, respectively. Milk production generated daily incomes that covered daily operation costs of farms, as well as the economic needs of the farming family. Calves represented important incomes that ranged between 30 and 50% of total annual farm incomes, cashed in once or twice a year. Milk production provides economic stability to DPF, whereas FL and low input use are key elements that allow low costs in the production of milk and calves in DPF in Central Mexico.