Purpose – the purpose of this study is to analyze the relationship between the quality of internal control and performance of commercial banks in the U.S.Methodology – the paper analyses the reports on internal control over financial reporting of 30 U.S. largest publicly traded banks during the period 2013-2017. The study also examines social media for any news related to the banks internal control issues. The research applies the COSO Internal Control Framework for classifying identified control deficiencies. It uses a regression analysis to investigate whether there is a relationship between identified deficiencies and banks’ performance.Findings – overall, the study finds a negative impact of identified deficiencies in risk management and information and communication components of internal control system on bank performance.Originality/value – the study contributes to a limited research on the impact of internal control system on bank performance. Moreover, the research focuses on a recent performance period. The majority of existing studies focuses on earlier post-Sarbanes-Oxley Act period. The issue is particular important for Kazakhstan, where a regulatory requirement to report on quality of banks’ internal control systems’ quality is absent.