he selection index methodology is the best approach to increase profit in animal production by genetic selection due to the use of economic values for breeding goals. The aim of this study was to derive economic values through a deterministic bio-economic model in order to construct an economic selection index for dual-purpose Simmental cattle. Phenotypic, genetic and economic information from the Colombian Simmental genetic evaluation were used in this investigation to design a base production system. The economic values for weight at eight months of age, age at first calving, first lactation milk yield and first calving interval were obtained by calculating the partial derivatives of farm profit with respect to each trait, the relative economic importance for each trait was 43.45, 15.29, 5.33 and 35.93%, respectively. By increasing the selection index by one dollar, the milk yield contributed the most to genetic gain with an increase of 10.36 L, while the lowest genetic gain was found for the weight at eight months of age with an increase of 0.088 kg. The milk yield had the greatest economic contribution worth 0.642 dollar for each USD of increase in the index. The economic values and the final selection index provided favorable genetic and economic progress for milk, beef and reproductive traits in Simmental cattle under tropical conditions. Likewise, estimated economic values can be used to make decisions on the selection of foreign bulls to similar Simmental production systems.