An important control mechanism of every country is the state audit. Control of the credibility and correctness of financial statements is carried out by supreme auditing institutions. Supreme audit institutions in the implementation of state audit are primarily focused on financial statements and operations, as well as on the most successful improvement of the efficiency and effectiveness of entities that manage public assets, but also on how exactly these audit entities apply laws and other regulations in the public sector. The aim of the paper is to compare the specificities of the state audit and supreme audit institutions of the French Republic and the United Kingdom. The common characteristics of the observed supreme audit institutions are found in the partial application of auditing standards such as ISSAI 100 Fundamental Principles of Public Sector Auditing, ISSAI 200 Fundamental Principles of Financial Auditing, ISSAI 300 Fundamental Principles of Performance Auditing and ISSAI 400 Fundamental Principles of Compliance Auditing as well as other application guidelines of these standards. The main difference between these two supreme audit institutions is in their organizational structure. The Supreme Audit Institution of France is organized as a court of auditors with judicial powers, while the National Audit Office of the United Kingdom is organized as a monocratic office. The conducted financial audits and efficiency audits were also compared.