Fringe areas of urban regions increasingly occupy the attention of contemporary urban-geographic research. The focus of this paper are rural settlements of suburban space, from the aspect of their demographic and functional transformations. One of the scientific goals is to point - through populational and demo-social indicators - to the impact and spread of urban transition from the periurban to the rural zone, which means spreading of (Belgrade) urban region as well. The first part of the paper defines the rural-urban belt as a complex physical space with complementary social economical and spatial elements. The second part of the paper is a case study of villages in the northern part of Belgrade metropolitan area (on administrative territory of Vojvodina province), which will point to demo-functional indicators of recent urban transition. Transition of periurban space can be spatially reflected as changes in land use, e.g. transformation into periurban agricultural area. Methods for estimation of the level of urban and functional development of the mentioned rural settlements will be applied in the paper. The results will show that the group of the studied rural settlements demo-functionally fits into Belgrade urban region.