This paper follows our previous article, Kotlán and Machová (2012a), which presented an indicator of the tax burden that can be used as an alternative to the tax quota, or for implicit tax rates in macroeconomic analyses. This alternative is an overall multi-criteria index called the WTI -the World Tax Index. The aim of this paper is to present the new World Tax Index 2013 and its methodology, which allowed us to compute it for all 34 OECD countries for the 2000-2012 period, with special references to methodology changes from the previous version. We show that, using the WTI, the highest tax burden is measured for Denmark, Belgium and Turkey, while the lowest tax burden is in Switzerland, Ireland, Chile or Japan. The total ranking of the countries is from 66% correlated with the ranking according to the tax quota, mainly due to a strong correlation in the case of property taxes, personal income taxes and VAT-type taxes. In these cases, the tax quota seems to be a good approximator of the tax burden. However, there is no correlation between corresponding tax quotas and WTI sub-indices for corporate taxes or selective consumption taxes. In those cases, the tax quota apparently fails and is not suitable for use in further analyses.