This paper describes how to build multisector computable general equilibrium models for policy analysis. The article presents the social accounting matrix (SAM) that provides the conceptual framework linking together different components of the model and furnishes much of the data as well. This is followed by the equations of the core CGE model and by a description of how the core model is implemented using the GAMS software. The article proceeds to describe how the model’s benchmark data and parameters are derived from the SAM. The final section uses data from an African country to consider how the GAMS model can be applied to evaluate the