The article aims to explain whether in 2004–2015 Poland experienced economic convergence between regions and counties (Polish: powiat), and whether this process occurred within the regions (Polish: województwo). Following Poland’s EU accession, the Polish policy became dominated by the polarization and diffusion concept of regional development, which may cause differences in the short term, while in the long run it may contribute not only to the increased efficiency of public funds allocation, but also to the elimination of disparities in growth levels. In the analysed period Poland experienced a process of economic divergence between the regions, only the years 2006–2008 saw a short-term reduction in regional disparities. On the other hand, a slow process of reducing economic inequalities between counties took place after 2004. It was, however, varied – a clear reduction in disparities occurred between the land counties (Polish: powiat ziemski) in an almost monotonic manner, whereas city counties (Polish: miasto na prawach powiatu) did not undergo any convergence. Within the regions, the process of economic convergence varied: in five regions, β-convergence was identified, and σ-convergence occurred in all the regions. The process of reducing disparities was significantly dependent on the development pathway of the region.