There is a lack of methodologically grounded and generally accepted regional competitiveness’ evaluation method in Latvia. Common feature of the research about nature of competitiveness is that competitiveness of a region depends on how high and sustainable the level of prosperity in the region is. The analysis of scientific literature showed, that most often synthetic indexes are used to evaluate competitiveness of a region. Methodology to evaluate regional competitiveness was developed and approbated in case of Latvia. To identify the most appropriate method for competitiveness index calculation, Regional Competitiveness Index (RCI) according to two different methods was calculated in the research. The results obtained were similar, but each of index calculation methods has its own advantages and disadvantages and the choice of the appropriate method will depend on the researcher's goals and objectives. Use of relative weights in index calculations affects the obtained results, therefore, necessity of relative weights must be economically justified. It was proven that regional competitiveness cannot be characterized by such simple indicators as GDP or GDP per capita. RCI shows the level of competitiveness of Latvia’s statistical regions, it is possible to compare regions in time and among each other. It allows to form regional development policy and strategy more reasonably.