The purpose of this chapter is to assess the spatial diversity of the economic development of voivodeships and oblasts in 2004-2016. The measurement of the spatial diversity of economic development of voivodeships and oblasts was made by calculating and analyzing the taxonomic indicators of economic development for these regions. These indicators are based on macroeconomic variables such as the GDP per capita, level of wages and migration, investment rate and unemployment rate, which were taken from the state statistical offices of Ukraine and Poland. The level of economic development of the Polish and Ukrainian regions is significantly diversified in both space and time. The results of this taxonomic analysis show significant disparities in the economic development of these regions. This analysis leads to the conclusion that both in Poland and Ukraine, the most advanced regions in terms of economic development include industrial zones and areas with a highly developed service sector. The results of the conducted research also indicate that in these two countries, a high level of economic development can be seen both in the capitals and in their surrounding regions (the Mazowieckie Voivodeship and the Kyiv Oblast). The clearly less developed regions of both countries include those where the agricultural sector prevails.