The present research had as objective, to compare checking cost methodologies and identify the milk production scales in the main states that produce milk in Brazil. The function of cost production of milk activity was estimated considering two methodologies, determined by: “milk activity cost” and “milk center cost”. The technical and economic results of 162 producers were analyzed from August 2000 to July 2001. The cost investigation by the methodology of “milk center cost” made possible a bigger accuracy related to the analysis of the total medium cost in the milk production. It was clear that earnings occurrence with the production scale. The results make clear that the study is formed by producers that look for greater productive efficiency and that there is an even profit possibility when talking about better allocation and improve-ment of the resources. The indicators analysis pointed that the reduction possibility of medium cost is more significant for the production global system, that is, to the milk activity, than to the milk subsystem making clear that the other subsystems of the global activity presented a worse use of the resources than the milk production subsystem.