The idea that ports might be a factor of regional economic development has been discussed for the last decades. This paper contributes to the studies of regional economic development by exploring how ports’ cargo turnover affects basic indicators such as gross regional product, level of employment and job creation. Authors compare two north-western Russian regions (St. Petersburg and Leningrad Province) and two western European regions (Antwerp Province and Groot-Rijnmond) for the period 2000–2015. Practical implementation of regional studies for Russian and European Union ports was conducted with the use of statistical methods. The findings do not support the thesis that ports play a crucial role in regional economic development generally, but they do indicate some economic similarities across the selected regions. Authors conclude that the ports under consideration vary in their impact on regional socio-economic development. The case of Saint Petersburg and Leningrad Province does not fit with the general hypothesis due to very little industrial activity in the ports’ zones and federal ownership on the general ports’ assets.