Introduction. Severe mechanical trauma is one of the major medical and social problems of modern society, resulting in more than 5.8 million deaths worldwide each year. The leading cause of potentially preventable death in these victims is uncontrolled post-traumatic hemorrhage. Research materials and methods. The experiment involved 32 healthcare professionals with 0 to 18 years of practice experience. Participants were presented with five step-by-step scenarios of varying blood loss, followed by a visual assessment of the blood loss. The time for viewing each scenario was short, which allowed us to reflect the time constraints experienced by prehospital medical personnel when providing emergency care to a victim at the scene. For each assessment, the standard error was calculated (absolute value (estimated volume ‒ actual volume) / actual volume × 100). Research results. In most scenarios, we observed an overestimation of small blood loss. At the same time, large volumes were underestimated. The average standard error was 127.9 % with a range of 49.2 % to 164 %. Sufficient accuracy of assessment was determined to be within 20 % of actual blood loss. Only in 51 cases, or 31.88 %, was the estimate within 20 % of the exact value. The most accurate estimates were for the scenario with a simulated thigh wound on asphalt (62.5 % correct) and the worst for the scenario with a mannequin wearing a T-shirt with one-third of the front soaked in blood ‒ no correct answers. Conclusion. Visual assessment of blood loss is too imprecise to be considered clinically useful. Practical experience does not improve the ability to make a more meaningful assessment in this limited study.