This paper reviews the literature and presents empirical results of survey ofeconomic base in Opolskie Voivodship (Poland). To estimate the economic base ofOpolskie Voivodship, the location quotient is used. This study uses data from theCentral Statistics Office of Poland (CSO). The data by kinds of activity are presentedin accordance with the Polish Classification of Activity (PKD 2007). The mainpurposes of the study are: (1) analysis of diversification and changes in employment inenterprise sector (especially in manufacturing), (2) identification of basic and nonbasicsectors in Opolskie Voivodship in 2008-2010 period.