OBJECTIVES: When contracting with large accounts, manufacturers have long understood the importance of discounting to gain the favor of high-volume customers over the competition.  The objective of this research is to compare what levels of discounting is necessary to sell pharmaceutical products in the highly-competitive cancer-supportive care market to the leading public payers in two of Latin America’s largest markets, the Sistema Único de Saúde (SUS) of Brazil and the Instituto Mexicano del Seguro Social (IMSS) of Mexico.  As the level of concentration in terms covered lives as a percentage of their respective countries’ total populations varies this will provide insight into the importance that concentration plays in securing greater discounts. METHODS: Quantitative analysis of SUS and IMSS tender purchase data compared with ex-manufacturer prices for selected cancer supportive care agents in Brazil and Mexico.  Products will be divided into innovative and commoditized baskets to provide insight into any differences that level of differentiation may play when contracting with these payers. RESULTS: Due to its higher concentration of covered lives to total population, discounts on sales for the selected products to SUS were greater than on those to IMSS.  This was true for innovative as well as commoditized products, although differences in coverage policies for higher-cost, innovative drugs result in greater variability of data than for the commoditized basket of products. CONCLUSIONS: Discounting plays a critical role in securing contracts with large accounts, and is even more important with payers that cover a larger proportion of their populations.  This is especially true for commoditized products, while innovative products show greater ability to avoid more pronounced discounting with even the largest public payers in the countries due to their greater level of differentiation.