This paper describes the construction of a Social Accounting Matrix (SAM) for the Mexican economy for year 2008. It presents the methodology and data sources used, assumptions made, criteria adopted to disaggregate the SAM’s accounts and the main results obtained. The Mexico SAM was built as the main data base for the calibration of a Computable General Equilibrium (CGE) Model, used to investigate the quantitative effects of climate change on the Mexican economy, with emphasis on analyzing its distributional impacts. Since the effects of climate change are mainly transmitted to the economy through the agricultural sector and since impacts on agriculture differ across regions, the Mexico SAM presents a significant disaggregation in the accounts referred to the agricultural activities and to income distribution, redistribution and income spending across households and regions. The final disaggregated SAM is quite large and is included in the accompanying spreadsheet file.