In the master thesis, we modelled Travel-To-Work-Areas (TTWA) in the programming language R. Travel-To-Work-Areas represent areas where the majority of working population lives and works. The TTWA method was used in the process, therefore four input parameters were defined (minimum and target number of the working population and minimum and target level of self-containment). The commuting flows data between municipalities was used to model the local and regional Travel-To-Work-Areas in Slovenia for years 2004 and 2016. A total of 14 sets of results were gained with different sets of input parameters, which were based on the Strategy of spatial development of Slovenia (SPRS, 2004) and local labour systems proposal of the RePUS project (Pichler Milanović et al., 2008). The results’ comparison between 2004 and 2016 shows a reduction in the number - and consequently an increase - of the Travel-To-Work-Areas in Slovenia. At the same time, the number of the working population number is increasing and the level of self-containment is decreasing in the Travel-To-Work-Areas.