This paper aims to analyse the spatial interaction of Romanian Cities from 1948 to 2021 trying to perceive if, along seven decades of quite different political regimes - from Central Planning to Market Interaction-, there have been changes in the logic of spatial interaction between City Regions. The study looks into the economic-demographic evolution of Romanian city regions and tests whether, throughout time, adding to the role of the economic base, their evolution follows a logic of size maximization, or a logic of maximization of interaction flows subject to the spatial structure of Romanian cities. Results show that the logic of spatial interaction changed during the period. Except for the first periods from 1948-1956-1966, the spatial evolution of Romanian City Regions is better explained by a logic of size maximization, either in the period of Central Planning (1966-1992) or in the period of Market Interaction where the population of the previous period, or the logic of size maximization, has a strong effect in the relative performance of city-regions when compare with the logic of maximization of interaction flows. Furthermore, exports play a more reduced role in regional growth when space is appropriately integrated.