Studies dealing with the issue of polycentric urban development, both functional and morphological, often promote different approaches to the measurement of polycentricity. Relying on data on commuting patterns and the intra-regional distribution of population in Poland in 2011, we apply two measures of polycentricity to shed more light on the functional and morphological development of urban regions in Poland. We also explore the relationship between the two dimensions of polycentricity, using a functional/morphological primacy index and a general functional polycentricity index. The results reveal regions for which the different measures suggest divergent conclusions, while also implying that the measure used can determine the strength and statistical significance of the relationship between the two dimensions to polycentricity. As, in our view, it is the measure advocated by Burger et al. (2011) that best seems to differentiate between the different forms of urban structure, we use this to summarise patterns of polycentric urban development in Poland. The results illustrate: the statistical significance of the relationship between the two (morphological and functional) dimensions to polycentricity in Poland’s urban regions, and the way in which the level of functional polycentricity is higher than the degree of functional polycentricity.