An important goal of communist economic policy was common and mass industrialization oriented on minimizing developmental inequalities between regions. Thus, the goal of this paper is to examine whether the modernization efforts of the Communist Party reduced (as planned) or rather exacerbated the economic inequality between regions. The authors use the existing data on regional income and employment structure to reconstruct the spatial structure at the voivodeship level. They use the 1976–1997 administrative division (49 small voivodships) and project backward estimates of regional income using data on employment structure and population. The results confirm regional convergence between 1950 and 1986. It was correlated with rapid growth in investment spending. The decreasing regional economic disparity between 1976 and 1986 was also related to the 1975 administrative reform. But, as the authors point out, the results confirmed, that in comparison with Western European countries the dynamics of convergence, and thus the scale of inequality reduction in Poland was only comparable to developed capitalist countries.