This paper simulates the medium- and long-term impact of proposed and expected energy policy on the environment and on the Mexican economy. The analysis has been conducted with a Multi-sector Macroeconomic Model for the Evaluation of Environmental and Energy policy (Three-ME). This model is well suited for policy assessment purposes in the context of developing economies as it indicates the transit ional effects of policy intervention. Three-ME estimates the carbon tax required to meet emissions reduction targets within the Mexican “Climate Change Law”, and assesses alternative policy scenarios, ach reflecting a different strategy for the recycling of tax revenues. With no compensation, the taxation policy if successful will succeed in reducing CO2 e missions by more than 75% by 2050 with respect to Business as Usual (BAU), but at high eco nomic costs. Under full redistribution of carbon tax revenues, a double dividend arises and t he policy is beneficial both in terms of GDP and CO2 emissions reduction