Background: chronic kidney disease (CKD) has been associated with an increased risk of death and cardiovascular events, but its relationship with non-vascular outcomes, including functional impairment (FI), is less well understood.Objective: in this study, we review the association between CKD and FI, adjusting for potential confounders and risk factors, with a primary outcome of impairment in any instrumental ADL (IADL) or basic ADL (BADL).Design: the Cardiovascular Multimorbidity in Primary Care Study (CLARITY) is a cross-sectional study of community-dwelling adults.Setting: participants were adults living in the West of Ireland attending university-affiliated general practices.Subjects: all participants were adults aged >= 50 years living in the community.Methods: CKD was defined as an estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m(2). A standardised self-reported health questionnaire to measure activities of daily living (ADL) was completed by participants. Logistic regression analyses were used to determine the independent association between CKD and FI.Results: a total of 3,499 patients were included with a mean age of 66.2 +/- 10.3 years. 18.0% (n = 630) had CKD (mean eGFR 50.2 +/- 9.2 ml/min/1.73m(2)), 21.9% (n = 138) of which had a diagnosis of CKD documented in medical records. 40.4% (n = 1,413) reported FI and multivariable adjustment showed CKD to be independently associated with FI (OR: 1.43, 1.15-1.78), impairment in IADL (OR: 1.43, 1.15-1.78) and impairment in BADL (OR: 1.39, 1.11-1.75).Conclusion: our study shows even mild CKD is associated with FI, independent of age, gender, co-morbidities, traditional vascular risk factors and cardiovascular events.