<em><strong>Objective</strong><em> To design a methodology to assess the impact of processes in the value chain of costs billed to third-party payors for drugs with greater participation in the total turnover of a health institution. <em><strong>Methodology</strong><em> It was based on the theory of value chain, defined by Michael Porter. To this effect, by analyzing information reported by the health service provider institution (IPS), a first documentary stage established the drugs with greater participation in billing, through the Pareto principle. <em><strong>Results</strong><em> Based on the analysis of the processes in the value chain of hospital drugs, a formula was proposed to identify those with the most influence on the final cost. <em><strong>Conclusions</strong><em> Based on the analysis of all processes in the value chain, this methodologically sound formula constitutes a tool that allows to take actions for a continuous improvement, leading to cost reduction and the generation of added value.