Regionalization of Serbia, as an instruments whose adequate use would contribute to a decrease in interregional differences in development of certain parts, represents a complex task, which is only to some extent finished by adopting bigger territorial parts in Serbia. This work is made for the purpose of presenting the problems with regional planning process deriving from inconsistency which exists between administrative territorial organization into districts of the Republic of Serbia and functional areas of regional centers defined by The Spatial Plan of the Republic of Serbia, issued in 1996, then functional urban areas presented in The Strategy of Spatial Development of the Republic of Serbia in 2009-2013-2020 and in The Draft Law of Spatial Plan of the Republic of Serbia in 2010-2014-2021. Moreover, the work compares the above mentioned spatial areas with planned regions, for which the drawing up of regional spatial plans is scheduled, namely with statistical macroregions, whose defining is one of the recently adopted decisions in the Republic of Serbia. The aim of pointing out to the above mentioned inconsistency in so far used concepts of regionalization, is to contribute to the quality of regional planning of development, as well as to finding solutions which would refer to establishing borders of smaller, meso-regional totalities, and also to the determination of authorities of both middle levels of administration in our country. .