The Sustainable Development Index (SD Index) represents one possible methodological tool for quantification and measurement the progress of individual countries on the way to sustainable development. The main aim of the SD Index is to provide the aggregated and balanced numerical expression of this topic. The SD Index is structured hierarchically: fifty-eight variables are grouped into 14 indicators (thematic areas), 7 major problem areas and the overall SD Index. It is calculated for 146 countries and expressed in relative scale between 0 - 1 (the higher value means the better progress towards sustainable development). By using the SD Index, the development balance in individual countries can be evaluated and thus priority areas for development aid and investment can be identified. The best SD Index values are identified for the developed countries of the North and Western Europe, Canada and New Zealand. The worst situation is in several countries of Africa, in Haiti and Cambodia. Thorough discussion of the underlying philosophy and methods used and evaluation of the information value as well as advantages and disadvantages in comparison with other mentioned methodologies (UN CSD set of indicators, UN CSD Dashboard, 2001 ESI Index) is necessary.