The paper provides an overview of the trend in the concentration of the total assets of banks in Croatia for the period from 2007 to 2016 with the aim of analysing and presenting the changes that occurred in the system. Also, the paper shows the theoretical framework of the indicators used in the research as well as the comparison of their obtained values. The data used to calculate the total assets concentration are taken from the Croatian National Bank. The concentration indices used in the study include the entropy measure, the Theil entropy, the Gini coefficient, the Pietra index, the Atkinson index and the coefficient of variation. The results indicate a very slight decrease in concentration over the past several years, while the coefficient of variation points to the heterogeneity of the system, as well as to inequalities among the banks, which are most evident in the size of banks assets.