ABSTRACT: The authors aimed to evaluate age-related differences in inflammation biomarkers during the first 72 h of hospitalization for sepsis. This was a secondary analysis of a prospective observational cohort of adult patients (n = 855) from 10 urban academic emergency departments with confirmed infection and two or more systemic inflammatory response syndrome criteria. Six inflammation-related biomarkers were analyzed—chemokine (CC-motif) ligand-23, C-reactive protein, interleukin-1 receptor antagonist, neutrophil gelatinase–associated lipocalin (NGAL), peptidoglycan recognition protein, and tumor necrosis factor receptor-1a (TNFR-1a)—measured at presentation and 3, 6, 12, 24, 48, or 72 h later. The median age was 56 (interquartile range, 43 – 72) years, and sepsis severity was 38% sepsis, 16% severe sepsis without shock, and 46% septic shock; the overall 30-day mortality was 12%. Older age was associated with higher sepsis severity: 41% of subjects aged 18 to 34 years had severe sepsis or septic shock compared with 71% for those aged 65 years or older (P < 0.001). In longitudinal models adjusting for demographics, comorbidities, and infection source, older age was associated with higher baseline values for chemokine (CC-motif) ligand-23, interleukin-1 receptor antagonist, NGAL, and TNFR-1a (all P < 0.05). However, older adults had higher mean values during the entire 72-h period only for NGAL and TNFR-1a and higher final 72-h values only for TNFR-1a. Adjustment or stratification by sepsis severity did not change the age-inflammation associations. Although older adults had higher levels of inflammation at presentation and an increased incidence of severe sepsis and septic shock, these age-related differences in inflammation largely resolved during the first 72 h of hospitalization.