The author attempts to determine the size, structure and diversification of the economic base of towns and cities in the Warmińsko-Mazurskie Voivodship, as well as their evolution in the years 2008-2015. An additional objective is to determine the relationship between the level of economic growth of the examined units and the state of their economic base. The obtained results confirm the hypothesis that the economic sector is not a significant part of total employment in the surveyed units. At the same time, the exogenous employment structure is poorly diversified, and in the period under study it decreased even further, exposing local economies to external shocks. There is also a positive, although weak effect of the increase in local specialization on the level of revenue in local self-government units and on their level of unemployment.