The study regards the development of the Masovian Voivodeship which is the best developed voivodeship in Poland and simultaneously is diversified inwardly. The level of socio-economic development of all Masovian communes was defined on the basis of a synthetic index of development (z_i) for 2004 and 2010. Changes which appeared in the level of development of rural communes and other types of communes were analysed. The Local Data Bank (BDL) of the Central Statistical Office (GUS) served as the source of data used in the study. Urban communes have the highest level of development, but their dynamics of the development are relatively low in the analysed period. Every third rural commune belongs to the group of communes having the lowest level of development. Rural communes are prevailing among the communes which the lowest level of developmental changes. Simultaneously they are characterised by minimum values of the z_i indicator.