The subject and purpose of this final work are the principles and comparison of the organizational concept in the companies of Privredna banka Zagreb, Zagrebačka banka, Hrvatska poštanska banka and Erste banka. The core business of banks is everyday work with clients in the field of payment, payment of money, cash loans, the possibility of opening different savings and investments and the other. The aim of the paper is to establish the existence of a link between the heterogeneity of organizational structures of banks in the Republic of Croatia as well as the heterogeneity of bank operations in the Republic of Croatia. In order to study the area of work as efficiently as possible, research methodology will be carefully approached and the method of data collection will be selected. In this paper, practical knowledge and facts based on data from different sources will be used. The variable indicated in the research questions by correlation analysis will be studied. In this case, the number of organizational structures or employees will be affected by profits. Positive correlation may indicate the extent to which these variables increase or decrease parallel, which will also give a positive or negative answer to the research question. Observations will be conducted for the last ten years, i.e. from 2007 to 2017, the four largest banks in Croatia, namely: Privredna banka Zagreb, Zagrebačka banka, Hrvatska poštanska banka and Erste banka. The observation will be made on an annual basis. In the introductory part of the paper briefly describe topics that will be elaborated more in-depth through the work. The paper elaborates the basic concepts of bank, type and development of banking business in the Republic of Croatia, types and divisions of the business organization structure, and a few examples of organizational structures in banks in the Republic of Croatia. Four commercial banks were selected for comparison of their organizational structures in the Republic of Croatia. There will also be a correlation between the performance of the four largest banks and their organizational structure. The conclusion is an overview of the whole topic of this paper, which is based on the observation and study of the organizational structure of the banking system in the Republic of Croatia.