The aim of this paper is to compare the realized investments between Požega - Slavonia and Istria county. The paper defines the concept of investment and lists the types of investment. General statistical data on the mentioned counties, their investment environment and the most important economic branches are presented. An analysis and comparison was performed based on data on the structure of investments according to the National Classification of Activities 2007 in the period from 2011 to 2013. In addition, the counties were compared on the basis of realized investments according to the location of investment facilities and the seat of investors in the period from 2014 to 2018. This is followed by a comparison of the utilization of European structural and investment projects that the Požega-Slavonia and Istria county have contracted with the European Union in the period from 2017 to 2019. The paper mentions the most significant investment projects in the Požega - Slavonia and Istria county that are financed from European Union funds. The penultimate chapter discusses the connection of counties on the basis of already established examples of cooperation and several possible examples in the future at the suggestion of the author. Finally, in the last chapter, a conclusion is presented based on a comparison of the analyzed data on investments and potentials between Požega - Slavonia and Istria counties, and the author 's own opinion is presented.