When studying the rank-size relationship in the settlement system, principles like hierarchy, centrality, and specialization should be the prevailing instruments, whilst primacy should be considered just to a lower extent. According to the NPSP (National Plan of Spatial Planning) in the Turda - Alba Iulia Corridor there are settlements of rank II, III and IV, correspondingly municipalities as county capitals, other municipalities and towns. According to the NPSP, rank II may correspond to differently ranked localities, such as Alba-Iulia and Aiud. However, the first mentioned clearly has a larger size from the perspective of administration, service, and equipment facilities (hospitals, supermarkets). The relationships between the urban centers in the Turda - Alba Iulia Corridor can be grouped into four categories: county subordinate relationships, relationships of inter-county independence, relationships of local competition, and local collaboration relationships. The subordination relationships prevail in Alba County, as they are induced by the hierarchic position of its capital town, Alba Iulia, which is a classical case of administrative subordination. The independence relationships are developed between the urban settlements in Cluj County and those in Alba County. Relationships of competition appear mainly between the urban centers in the same county, both in Alba and Cluj. Relationships of collaboration are developed between Turda and Campia Turzii towns, although relations of competition were also identified between these two.