Changes in the tax structure and category of taxes clearly matter when it comes to initiating tax policies. This paper employs data from a sample of 33 transitional countries over the period 1991-2014. It finds that, in a particular transitional country, the higher the national income, the degree of openness, the share of the non-agricultural sector, the rate of population growth, the extent of urbanization, the density of population, the proportion of younger population, and the employment rate, the higher the ratio of taxes to GDP. Moreover, GDP per capita growth can bring about changes in the tax structure of a country. The findings also indicate that determining the causes of change in the composition of tax revenue during the course of economic development as indicated by GDP per capita growth is helpful in creating a more effective tax revenue mix in transition economies.