Mild cognitive impairment and Alzheimer's disease contribute to cognitive decline in the aging population, affecting 10–20% of adults ≥60 years and 50 million individuals globally, respectively. Chronic inflammation is implicated in their pathogenesis, but relationships remain unclear. This study examined longitudinal associations between inflammatory biomarkers and cognition in 4228 English Longitudinal Study of Aging participants over two- and ten-year follow-ups. Mixed-effects models evaluated C-reactive protein, ferritin, fibrinogen, and white blood cell count in relation to memory, executive function, processing speed, and overall cognition. The results indicated cumulative inflammation-related cognitive decline in adults aged ≥75 years.