Introduction: Procalcitonin production is induced in response to exposure to microbial toxins and certain cytokines (IL-1β, TNO- α and IL-6), after which it enters the bloodstream where it can be quantified. In COVID-19, high levels of PCT during antimicrobial therapy, especially in the absence of a tendency to reduce them, are an important prognostic factor, especially in elderly patients and patients with severe chronic diseases. Purpose: to study the level of procalcitonin and interleukin-6 in elderly and senile patients with a confirmed diagnosis of COVID-19. Materials and methods: Blood was tested in 305 patients with a confirmed diagnosis of COVID-19. Criteria for not including patients in the study: history of systemic autoimmune, oncological diseases. All subjects were divided into three age groups: 1 group (persons under 59 years of age) - 54 people, 2 group (persons aged 60-74 years) - 126 people, 3 group (persons over 75 years of age) - 125 people. Diagnostic sensitivity and specificity were assessed by ROC-analysis, with maximum area estimated from the curve. Sets of quantitative indicators, the distribution of which was different from normal, were described using the median and lower and upper quartiles. Results: An age-related comparative assessment of IL-6 and procalcitonin levels among COVID-19 patients showed an upward trend: concentrations of both analytes increased with age. The increase in IL-6 level averaged 42.15 pg/mL, for procalcitonin the same indicator is 0.665 ng/mL. In addition, a significant association was found between the level of inflammatory markers studied and the outcome of a new coronavirus infection. With age, the adverse outcome of the disease is accompanied by higher levels of the analytes in question. Thus, among middle-aged people with an unfavorable outcome of COVID-19, the level of IL-6 was 1.65, and the PCT was 5.44 times higher compared to the group of patients with a favorable outcome. At the same time, for elderly people, similar changes were 2.68 and 7.75 times, respectively, and for people of senile age - 4.72 and 9.56 times, respectively. Conclusions: The findings demonstrate the prognostic value of interleukin-6 and procalcitonin in both middle-aged and older-aged individuals. The diagnostic value was determined through ROC-analysis: an acceptable level of informativity was determined for procalcitonin, for IL-6 - a weak level of informativity, this pattern is true for middle-aged and elderly patients.