Our research focuses on the problems of modern spatial, social and economic marginalization of the Belgrade slum population, as well as on the measures of improving the living conditions in them. The slums on the territory of Belgrade are numerous, dispersed, heterogeneous in structure, size and type, and the common denominator that could express the typical situation is poverty of their population. The paper also included an analysis of the causes of the spatial concentration of slums, the increase in population, exclusion of the population, poverty and the attitudes of the Belgrade population toward these settlements and their inhabitants. A significant part of the paper refers to the main life problems of the Roma, but of the Ashkali and Egyptians as well, who mostly inhabit the slums (unemployment, illiteracy, begging, poor housing conditions, health problems etc.). Measures for improving the living conditions in Belgrade slums, aiming at the integration of their inhabitants into the spatial and social space of Belgrade are proposed in the final part of the paper.