The article is devoted to the analysis of methods for evaluating essential performance of mechanical tourniquets to improve their safety in use. According to the legislation of Ukraine and the European Union, a tourniquet is a medical device that, regardless of design, provides relief to a patient in the event of an injury by stopping bleeding in the limb by applying mechanical pressure. Tourniquets are classified as pneumatic and mechanical depending on the method of creating external pressure. The article considers a typical design of mechanical tourniquets and identifies the main structural elements: a pressure generating mechanism, a pressure element, a fixing device, and a place for recording the time of application. The analysis of scientific articles shows a significant number of studies focusing on the characteristics of pneumatic tourniquets, while methods for testing the effectiveness and safety of mechanical tourniquets have been insufficiently investigated. It is noted that the safety of medical devices is defined as the absence of an unacceptable level of risk for the operator and the patient, where risk means the effect of uncertainty in achieving the goals in the process of development, production, design, and use of a medical device. A list of essential performance of mechanical tourniquets is provided: overlapping pressure, pressure loss after application during the time of use, pressure gradient. It has been established that to date, four methods are known for obtaining measurement information on essential performance of mechanical tourniquets: a method based on converting the pressure value generated by the tourniquet during application into an electrical signal using strain sensors; a method based on measuring air pressure in a test cuff; an indirect method for determining pressure using Lamé's equation; a method for directly measuring pressure in the limb under the tourniquet using an invasive pressure sensor. Based on the identified essential performance of mechanical tourniquets, the requirements for methods of their determination are presented: measurement of overlapping pressure, determination of pressure loss after the tourniquet is applied during the time of use, determination of pressure gradient, reproducibility, repeatability, evaluation of metrological uncertainty, and evaluation of the essential performance of mechanical tourniquets based on mathematical models. Ways to improve the existing methods for evaluating essential performance are considered.