Regionalization is an exceptionally complex and contradictory matter, and at the same time becoming very challenging in the last few years in conditions of accelerated changes in the world. It is believed that regionalization today is an unavoidable strategic action of directing development processes on a territory. One of the aims of regionalization is to bring economic, demographic and social development processes into accord. Discordance of demographic transition courses with economic development caused prominent changes and complex development problems on the territory of Serbia, which indicate that appropriate attention should be devoted to demographic occurrences and processes in the approach to its regionalization. Proceeding from this fact, the goal of this paper was to identify the problems of regional differentiation of geoterritory and determine the place and role of demographic regionalization in the procedure of scientific knowledge, territory differentiation and organization of geoterritory; to set the general definition of regionalism from the demographic aspect, in the sense of theoretical concept based on empirical research, so as to obtain a scientific framework for research and functional approach to recognizing contemporary problems of development and organizing population; to decide on principles and elements, and point out to the content, purpose and goals of identifying demo geographic regions, in a way which would be adequate for planning regional development and organizing geoterritories. Such a set research goal required that the total problem of demo geographic regionalization is set on a wider theoretical, but analytical context, which is defined by mutual dependence of demo geographic with other regional systems, as well as with global questions of regionalism and integration ways. Demo geographic regionalization is carried out on the basis of numerous research findings and corresponding empirical results, with an idea that it serves as a basis for macro regionalization, general geographic or administrative-management regionalization, as a "foundation" for territory planning or development policy. Global and specific perception of numerous relevant components of regionalization had been carried out, with a favorable circumstance and significant basis being the following research up to now: "Outline of constant regions for demographic research" and the study of the Geographic Institute "Demographic bases for regionalization of Serbia". Unlike demographic regionalizations, this paper insisted on demo geographic as a more complex approach, and a concrete contribution of this paper refers to defining basic principles and elements of regionalization whereby in the process of delimiting regions, numerous geographic, natural geographic, anthrop geographic, territory-economical and territory functional relations and connections, occurrences and processes were articulated apart from demographic. Although not shown in the paper, regionalization of various demographic, territorial-demographic and demo economic traits were carried out for the purpose of research, which were to show to what extent, in what direction, according to which principles and in what way it is possible to carry out demographic regionalization in Serbia. It should be noted that most research on the topic of demographic regionalization indicate that the importance of certain elements of regionalization is variable and that is dependent on the regional level, and that the population change during demographic transition imposes a necessity for introducing new indicators and elements of regionalization. Having in mind all the stated elements, territorial-functional relations, realized territorial-demographic structure of Serbia and tendencies of demographic courses, as well as territorial plan of isolated macro regional centers, confirming the homogeneity of demographic development of various regions, but also researching migration flows under the influence of push and pull factors during the process of industrialization, urbanization and land reclamation, the only possible demo geographic regionalization of Serbia was presented. The isolated regions are homogeneous in the sense of functional interdependence, because each represents a region which is territorially-functionally connected to a regional center; and heterogeneous of structure, because each region represents a symbiosis of urban, rural and transitional type of structure, which are a result of differentiation of development and demographic processes, and which imply a corresponding demographic development, dynamics and composition of population. The goal of this paper was to give theoretical-methodological frameworks and a broader basis for integration of certain territorial units into unique demo geographic regions of Serbia, which would still be in the function of complex regional research and regional planning. Anything more than that (especially from the aspect of micro or macro regionalization) would require a team work of a larger number of experts, an extensive statistical-analytical and research project, as well as sound knowledge of various local conditions, historical-geographic and civilization events which often require deviation from consistent application of formulated criteria and measures for regionalization. This means that the given proposals should be understood as a principled scheme, a general framework of the demo geographic regionalization of Serbia on the basis of interdependence of natural and economic wholes, their geographic-transportation and economic-gravitational connection, development processes and demographic courses. Every concrete requirement in future practice of planning or organization of geo-territory would require defining goals and principles of regionalization as well.