Successive enlargements of the European Union have led to increasing heterogeneity of the development levels of the states and regions members. The Romanian development regions are among the most poorly economically developed European regions and are regarded as economies based on production factors where the development of economy is mainly triggered by the poorly qualified labour and the natural resources. This paper aims to analyse and to identify the factors lying at the bottom of regional development and the causes of Romanian regional disparities, by comparative analyse and the break down the basic development indicators into their components. The regional economic disparities from Romania tend to be more prominent due following causes: low level of development of most regions, structure of economy dominated by economic sectors with a low productivity; the low research-innovation potential; the low share of the population having a higher education, reduced capacity of the poorly developed regions to withhold the highly qualified labour, the weak development of infrastructure, particularly poor quality of infrastructure networks. Romania stays anchored in a development model characterized by an anachronous economic structure, a poorly qualified labour, a slow accumulation of capital and a reduced sustainability of the development rate.