Currently, there is a highly competitive market, which suggests that companies need to conform to this competition by optimizing their processes, principally aimed at reducing their costs. Historically, the cost management of a company has always had an accounting focus, primarily for tax compliance and tax requirements. But, this kind of costs visualization does not offer facilities to the manager act in process improvement nor supports operational decisions, whereas aggregates operational information and allocates indirect costs randomly. As the improvement of management costs becomes necessary, new methodologies of cost allocation appeared, from which the ABC (Activity Based Costing) Method, which proposes to allocate indirect costs by activity, will be emphasized in this work. Resulting from this method, we can check the profitability of customers through the Cost to Serve, that after the allocation of costs by activities, it is linked to the object of analysis, which, in this case, would be the client. Thus, this work proposes the implementation of a model for measuring the Cost to Serve in the supply chain of Petrobras, a Brazilian oil company that is considered one of the ten largest companies in the world. As in most part of the companies, the practice of cost management at Petrobras does not allow, for example, managers to have an overview of the operational failures of processes, as well as which customers are more profitable or which are the more costly routes. Some cost indicators are monitored, but these do not enable these types of analysis. Thereat, it was defined metrics for measuring the costs, as well as modeled an analysis tool to measure the Cost to Serve. Some simplifications were established to become viable the implementation and some points were presented about using an existing tool for the model and the development, by the company itself, of a completely customized solution. The work ends with some suggestions for the implementation of the tool as well as suggestions for further development and deployment around the subject.