This paper is based on the National Identity Module Survey ISSP 2003. Using the Theory of Social Identity, we developed a multidimensional concept of national identity. This concept was defined including four dimensions, which were verified by the method of Factor Analysis and reflected in their respective indicators. Analyzing the personal characteristics of individuals as determinants of national identity through the estimated five probit models, it was found that older people are more likely to have a high degree of national identity. For its part, the level of formal education has a negative impact on the level of national identity, while gender is not significant at the time to explain this variable. Concerning the analysis of indicator of national identity at the level of the sample countries, the location of Uruguay above average, ranked 12th. among the 34 countries surveyed must be highlighted. By decomposing the overall indicator, it is emphasize a high requirement of Uruguayans when considering another individual as truly Uruguayan, and a low level of extreme nationalism.