Rationale: Prior research has suggested an association between chronic obstructive pulmonary disease (COPD) and the development of cognitive decline; however, these studies have been cross-sectional or small case-series. Objectives: To determine whether COPD increases the risk of cognitive decline among older adults surveyed in a large, population-based longitudinal cohort. Methods: We included data from the 1996-2002 waves of the Health and Retirement Study, a biennial nationally-representative survey. We studied respondents who completed cognitive testing in 1996 and at least one subsequent survey, and excluded those with unknown history of COPD. Clinical history of COPD was based on self-report; severity was categorized based on use of oxygen or disease-related activity limitations. Our primary outcome was cognitive performance, measured using a validated 35-point scale. We examined the effect of COPD on cognition using multivariable mixed linear models accounting for repeated measurements, adjusted for socio-demographic and clinical characteristics. Measurements and Main Results: 4150 adults were included in our study. Among them, 12% reported a history of COPD (29% severe, 71% non-severe disease). Upon repeated measurement, mean cognition scores of older adults with both severe and non-severe COPD were significantly lower when compared with adults without COPD (2.6 points (p<0.001) and 0.9 points (p<0.001) respectively). After multivariable adjustment, mean scores of adults with severe COPD remained lower (0.9 point (p<0.001)), whereas mean score of adults with non-severe COPD was no longer different (p=0.39) when compared with adults without COPD. Conclusion: Severe COPD was associated with lower cognitive performance on standardized measurement over time.