['End-stage renal disease has been associated with venous thrombosis (VT). However, the risk of VT in the early stages of chronic kidney disease (CKD) has not yet been investigated. The aim of this study was to investigate whether CKD patients with stage 1-3 disease are at increased risk of VT.', 'Eight thousand four hundred and ninety-five subjects were included in a prospective cohort study, in which renal function and albuminuria were assessed, starting in 1997-1998, and were followed for the occurrence of VT until 1 June 2007. CKD patients were staged according to the Kidney Disease Outcomes Quality Initiative guidelines, on the basis of 24-h urine albumin excretion and estimated glomerular filtration rates. Objectively verified symptomatic VT was considered to be the endpoint.', 'Of the 8495 subjects, 243 had CKD stage 1, 856 CKD stage 2, and 491 CKD stage 3. During a median follow-up period of 9.2 years, 128 individuals developed VT. The hazard ratios (HRs) for CKD stages 1, 2 and 3 were, respectively, 2.2 [95% confidence interval (CI) 0.9-5.1], 1.9 (95% CI 1.1-3.1) and 1.6 (95% CI 0.9-2.8) relative to those without CKD after adjustment for age, sex, body mass index, hypertension, diabetes, malignancy, and high-sensitivity C-reactive protein. Subjects with CKD stage 3 and albuminuria (≥ 30 mg d(-1)) had an adjusted HR of 3.0, and subjects with CKD stage 3 without albuminuria had an adjusted HR of 1.0.'] Do chronic kidney disease stages 1-3 increase the risk of venous thrombosis?