Summary. Understanding and eliminating sources of hemolysis is an important challenge in clinical laboratories. Despite individual studies identifying specific factors associated with hemolysis, there are practically no studies showing or refuting an increase in the likelihood of hemolyzed samples with increasing age of patients. Aim. To assess effect of patients age on the frequency of hemolyzed samples and level of electrolytes in tests of venous blood samples. Material and methods. The study was carried out retrospectively on 19864 blood samples from patients entering the laboratory of City Hospital №2 in St. Petersburg within 6 months. All sample of patients was divided into 4 age groups. The next step was the counting of hemolyzed samples for each group of patients. The number of samples with critical levels of potassium and sodium in a sample of 33653 patients admitted to the laboratory was estimated. The entire sample was similarly divided into 4 age groups. Results. As a result of data processing, the total relative number of hemolyzed samples by age was revealed for the studied period of time. A statistically significant difference in the number of hemolyzed samples was found between group 3 (from 60 to 74 years old) and 4 (over 75 years old), asymptotic significance = 0.016. The results of the study of critical electrolyte values show an increase in the occurrence of such results with the age of patients. Also, values of the levels of considered electrolytes differ statistically significantly in the groups under consideration. Discussions. According to the results of our study, it can be assumed that age partially influences the occurrence of hemolyzed samples. According to the data obtained, the percentage of hemolyzed samples is significantly higher in group 4. The results of the study of critical electrolyte values show an increase in the occurrence of such results with the age of patients. Also, the values of the levels of the considered electrolytes are statistically significantly different in the groups under consideration. Conclusions. In patients aged 75 years and older, hemolysis occurs statistically significantly more often in venous blood samples. With increasing age of patients, the number of samples with critical values of potassium and sodium increases.