Aim COVID-19 pandemic has caused extensive burden on public life and health care worldwide . This study aimed to assess circulating levels of inflammatory cytokines in adult patients who were hospitalized with COVID-19 and stratified according to age (older or younger than 65 years) aiming to explore associations between these markers of inflammation and comorbidities . Methods This was a retrospective cohort study of 142 COVID-19 patients consecutively admitted to the University Hospital of the Federal University of São Carlos, from July to October 2020 . Sociodemographic data, chronic comorbidities, and baseline NEWS2 and SOFA for clinical deterioration were obtained at hospital admission . Serum levels of inflammatory cytokines were determined by flow cytometry . Results Older adults with COVID-19 had higher serum levels of IL-6 and IL-10 as compared to those under 65 years of age (p <0.001 and p = 0.003, respectively). IL-10 was independently associated with age (p = 0.04) and severity of the disease (p = 0.05), whereas serum levels of IL-6 were not directly associated with age (p = 0.5). The comorbidity index seems to be the main responsible for this, being significantly associated with IL-6 levels among those aged 65 and over (p = 0.007), in addition to the severity of the disease . Conclusions Higher serum levels of IL-6 and IL-10 are associated with the severity of the disease and a higher comorbidity index among adults aged 65 and over with COVID-19. This should raise awareness of the importance of comorbidity index, rather than age, during risk stratification.