From Soviet demographic space to contemporary divisions. The present article examines the relationship which, prior to independence, existed among the various component peoples of the USSR ; a start is made with behavioral demographic patterns, in order to understand how they have influenced the contemporary situation. Two major aspects are examined. The consequences of the Russian presence in Central Asia are studied through changes in fertility rates, beginning with an enquiry on this subject carried out in Uzbekistan in 1992. This enables the authors to highlight the importance of medical and teaching institutions in the shaping of individual attitudes. In the second part, the article considers how the different levels of territorial division and the specific nature of the Soviet territory led to particular alignments of Soviet geographical space which partially anticipated the carving-up into fifteen states. This present study has been carried out by using detailed data from the 1989 census to analyze population movements between place of birth and domicile. In particular, it shows how republican frontiers could already, to some extent, be regarded as national frontiers.