Based on sixteen Polish provinces the author discusses, explores, evaluates and diagnoses the regional disparities in development of Poland’s provinces. First, four fields are studied, such as: demographic potential, social development, economic development and technical infrastructure. Next, the author compares sixteen Polish provinces in relation to the level of synthetic measure of socioeconomic development. Research covers the years 2006, 2010 and 2015 and has been conducted using statistical material provided by the Central Statistical Office. The research tools used in the article include literature studies, descriptive analysis and selected methods of multivariate comparative analysis. Multivariate comparative analysis has proved that Mazovia Province is a leader in terms of demographic potential and economic development, while Silesia Province takes the first position in both social development and technical infrastructure. The highest levels of synthetic measure of socioeconomic development have been observed in Mazovia Province and Silesia Province. In addition, the author presents theoretical aspects of socioeconomic development and discusses the relevance of regional policy.