Osterlits (Université de Paris III/CNRS) In this article I attempt to reanalyse data from the Euskal Herriko Soziolinguistikazko Inkesta (Basque Sociolinguistic Survey, 1996) using methodologies derived from the theory of integration as developed in relation to eastern European countries, such as Estonia and Latvia. The reworking of the data clearly points to significant differences between the northern Basque Country (Iparralde) in France and the Basque Autonomous Community (BAC) in Spain, despite apparently similar overall levels of bilingualism. The theory of integration highlights a number of points drawn from the sociolinguistic data, which suggest that the lack of a supportive language policy north of the Pyrenees is condoning ongoing language attrition whereas in the BAC the positive language planning measures to promote Basque are not only starting to yield encouraging results but also that there is a social project that enjoys a groundswell of support. Key Words: Basque, Sociolinguistics, Theory of Integration, Bilingualism, Assimilation, Separation, Segregation Pliuralism. In this article I am proposing a crosslanguage approach, applying to Basque both empirical and theoretical models developed in other parts of Europe in situations which, although partly analogous, differ markedly in various ways 1 . My aim is to reanalyse the results of the sociolinguistic survey of Basque (Euskal Herriko Soziolinguistikazko Inkesta henceforth EHSI) designed and coordinated by the government of the Basque Autonomous Community in the light of the theory of integration which has produced interesting results in the Baltic countries,