Indicators are widely used tools to measure the sustainability of a nation. The definition of a concept conditions strictly its measurement. Therefore, the definition of sustainable development will determine the appropriateness of the variables selected for its measurement. The first part of this paper explores why it is impossible, at the present time, to have a univocal definition and measurement of sustainable development. The second part is devoted to the analysis of a set of synthetic indices - Human Development Index (Hdi), Adjusted Net Saving (Ans), Environmental Sustainability Index (Esi), Ecological Footprint Index (EF) and Ecological Balance (EB) - that could offer a realistic frame for measuring the progress towards sustainability of nations, as well as a way of ranking their performances. In the third part of the study, based on the selected indices, a comparative analysis of a sample of countries is proposed, aimed at showing how the variables taken into account modify the countries performance in terms of measured progress and sustainability, and also comparing the resulting shifts in Italy’s rank.