This paper analyzes the Cuban model of sustainable development and explains the causes that made Cuba the only country that meets the conditions of sustainability according to the Worldwide Fund for Nature (WWF). The Human Development Index has three main components: quality of life (health indicator measured as life expectancy at birth), knowledge (education indicator measured as adult literacy) and the standard of life (economic indicator measured by the Gross Domestic Income). This paper analyses the aspects of the educational and health system of Cuba and also of its energy policies that explain the excellent scores of the Human Development Index. Cuba shows a Human Development Index of 0.8 with an Ecological Footprint of 1.8 gha. This is achieved with a Gross Domestic Income lower than other countries with similar Human Development Index. The Ecological Footprint of Cuba is mainly determined by the CO 2 and the agricultural land footprint. The paper shows how the economic transition, after the economic crisis of the early 1990s, was realized without significantly increasing the Ecological Footprint.