The article discusses the importance of internal audit in private enterprises to ensure effective management and control of business processes. It highlights the need for a comprehensive approach to internal control systems and management practices. The researchers analyzed the basic principles of internal audit and outlined its functions, methods, and procedures. They proposed a revised approach to defining the functions of internal audit in response to the demands of businesses in a crisis economy. The study emphasizes the importance of creative methods and innovative approaches in solving internal audit assignments. It suggests a multifaceted classification of internal audit based on customer demands, such as technical audit, organizational audit, and marketing audit. The research concludes that internal audit should adapt to different situations by using various forms like risk-oriented audit and business-oriented audit.