In this paper we reveal the importance of the method ABC in the determination of the cost of the products and to the process of management. The method ABC allocates the indirect costs to the products on a more real base than the volume of the production and it shows the relationship between the overheads and the activities that determine them. This method takes into account the factors that generate the costs, named cost-drivers. The method ABC can be applied in the enterprises that have big overheads, a diversified production, a high cost of errors and many competitors. This method is used by the cost management, the performance management, the Activity Based Management and by the administration control.