Double-tract is a type of residential unit which is characteristic of multiple-family residences. It is characterized by two closely and parallelly placed residential tracts, sharing a common staircase and lift communication, most often set normally in relation to the direction of tracts. Primary residential areas are, by rule, almost always oriented towards outer facades of the object, while secondary areas are oriented towards open, atrium interspace between the tracts. The first type of double-tract unit was built in 1957 in Belgrade by architect Milorad Macura, followed by a variation of this unit, mostly as a consequence of functional research and experimenting in architecture competitions, which were very popular during the second half of XX century in Serbia. Although in Serbia (and mostly in Belgrade), a large number of residential blocks and individual objects used double-tracts, this phenomenon has not been more significantly explored until now, either in habitology or historiography sense. This is why this paper will focus on the circumstances of its emergence and the reasons for the wide use of double-tract units in residential architecture in Serbia. The aim of the paper is to check the thesis claiming that the design of double-tract was a topic present in the second half of XX century in Serbia and whose use in most cases was not in accordance with the basic principles of orientation of double- tract unit in space, as well as look into reasons why double-tract unit was widely used in Serbia particularly.