In economic theory, a household is one of the basic business entities next to the enterprise and the state. Gross (non-financial and financial) assets as well as net assets (gross assets reduced by the size of debt) collected by the household have been studied by economists in terms of their impact on the growth of the society's wealth and economic development. The presented article includes the study of the countries belonging to the so-called old and new (ten countries that joined the EU after 2004) European Union, taking into account such values as: gross wealth, indebtedness and net assets per capita (per adult) as well as the dispersion of these values. The main source of output data was the Global Wealth Databook report prepared by the Credit Suisse Bank A.G. The gross per-capita assets in the audited period (2006-2016) increased in all EU countries by 108.9%, debt by 12.50%, and net assets 8.72%. Analysing the group of new EU countries that we were interested in, they recorded an increase in gross assets by 23.60%, debt by 38.00%, and net assets by 7.00%; and in the case of other EU countries adequately (gross assets 7,60%, debt by 10.00%, net assets by 7.00%). Although the countries that joined the EU after 2004 recorded a higher increase in gross and net assets per adult in relation to other countries, their position did not improve and they remained in the least prosperous zone during the entire period considered. In the analysed period, in the examined group of 27 countries, the discussed per capita figures of countries from the first quartile (only the countries from the new EU) exceeded the median by 10-15%, while the third quartile countries (only the old EU countries) exceeded the median by several times. This indicates huge disproportions in the wealth of citizens of the old and new EU countries.