Introduction. Systemically important banks determine the driving force of the entire banking sector of the country. Assigning a credit institution to such a category is not its advantage, it is its responsibility not only to customers, but also to society and the state. All commercial banks, which are grouped into a systemically important group, are large financial groups with large amounts of assets, the loss of which will definitely disrupt the functional structure of the country’s economy. Theoretical analysis. This article pays special attention to the definition of systemically important credit institutions, key aspects of their regulation, as well as approaches to assessing the financial stability of commercial banks. In particular, V. S. Kromonov’s methodology is considered in detail, which, despite the fact that it was developed a long time ago, can be actively used in modern conditions. Empirical analysis. The statistical indicators of systemically significant commercial banks are analyzed, as well as the data necessary to assess their financial stability using V. S. Kromonov’s methodology. The calculations made it possible to identify the most economically stable credit institutions, as well as to compile their rating. Results. The key aspects substantiating the importance of assessing the financial stability of systemically important banks are formulated. Disruption of their stable functioning can lead not only to the emergence of one-time systemic risks, but also to a decrease in the financial security of the country. The advantages and disadvantages of using V. S. Kromonov’s methodology in assessing the financial stability of systemically important banks are presented.