In-migration into the EU has become an important issue in recent decades, as an important component accounting for population changes in Europe. In contrast, it was after the fall of communism that out-migration grew into a major – but also relatively new – phenomenon affecting Romania. Especially after 2002, in which year Schengen visa requirements were waived, rapid growth in circular migration was encouraged; with a further migratory wave ensuing after 2007, due to free access to the European labour market. Against that background, work detailed in this paper has sought to provide insights into specific features of the process of out-migration, as this relates to social development. Use was made of statistical data available at NUTS 2 (Development Regions) level, as provided by the National Institute of Statistics; as well as various further data and information from both the World Bank and EUROSTAT. To achieve the objective specified above, efforts have been made to select indicators shown to offer a broad and accurate picture of both out-migration (via an out-migration rate indicator) and levels of social developmental (via a Socially Disadvantaged Index). The effects of what mainly proves to be temporary out-migration are very important, as they drive temporary loss of human capital, with Romania appearing in statistics among the main sources of labour-migration flows.