Internal control is the activity which, within the company and service of the company's management, controls the operations by adequate risk management (and opportunities). This activity involves the organisational structure and the selection the implementation of methods and procedures in order to ensure adequate risk management, conditions for good management, heritage preservation and reliability of information. After the review of principles and methods of internal control problems specific to different stages of the cycle of operations are discussed: cycle of funding, sales, purchases, inventory, salaries and wages. The key element in the approach concerns the analysis of risks and excellent risk management by the operational management. An efficiency evaluation of the organisation based on risk management analysis by the internal auditor completes the course.