The spread is a measure of the financial system intermediation costs and affects economic growth. this article evaluates the spread determinants for the colombian economy by the period 2010-2020. we use the dynamic data panel methodology and estimate several models with the generalized moment method (gmm). the results show that the macroeconomic environment, especially unemployment, and the operational efficiency of financial institutions are important factors to explain spread. furthermore, the market concentration of the financial system is also relevant to explain the intermediation costs.