Measuring progress of the tourism destinations in the area of sustainability has now become one of the major challenges facing policymakers action. Sustainability is a dynamic concept. In fact, in reality, it really can be measured is not â€?sustainabilityâ€?, but â€?progress towards sustainabilityâ€?, bearing in mind that this is not an ideal target linked to a fixed state of harmony, but a continuous process of adjustment and reorientation of tourism development to achieve the balance between the multiple dimensions that comprise it. The aim of this paper –after initially analyzed the major advances made in recent years over the concept of sustainability applied to tourism and its measurement- is to propose a methodology for dynamic analysis of sustainability of tourism. This methodology is based on developing a composite index through factor analysis. This composite index is powered by a set of indicators that includes the four dimensions of sustainability (environmental, social, economic and institutional) for the years 2000, 2004 and 2008. Thus, it is possible to measure progress towards sustainability (through the improvement of these indicators over time) of tourism destinations analyzed. To demonstrate the validity of the methodology, it has been applied to analysis of the sustainability of tourism in the Spanish regions, many of which (Balearic Islands, Canary Islands, Andalusia, Catalonia, etc.) have a high level of tourism development.