The prevalence and severity of chronic kidney disease (CKD) in primary care patients with diabetes or hypertension is unknown. AimTo assess the prevalence and severity of CKD in patients with diabetes and hypertension; and identify whether age, sex, diabetes, and hypertension are associated with CKD. Design of studyCross-sectional survey. SettingTwo Dutch primary health care centres (15 954 enlisted patients). MethodPatients, aged ≥25 years, with known diabetes type 2 (n = 471) or hypertension (n = 960), were selected on 1 October 2006. Initial screening uptake rates were assessed from the electronic patient records, and patients were invited when blood or urine measurements were missing. The presence of albuminuria was determined, glomerular filtration rate estimated, and clinical characteristics extracted. ResultsInitial screening uptake rates were 93% and 69% for diabetes and hypertension, respectively, and increased to 97% (n = 455) and 87% (n = 836) after active invitation. The prevalence of CKD was 28% in diabetes and 21% in hypertension only. The presence of diabetes was independently associated with albuminuria (odds ratio [OR] 4.23; 95% confidence interval [CI] = 2.67 to 6.71), but not with decreased estimated GFR (eGFR) (OR 0.75; 95% CI = 0.54 to 1.04). Age showed the strongest association with decreased eGFR (OR 2.73; 95% CI = 2.02 to 3.70). ConclusionIn primary care, more than one-quarter of patients with diabetes and about one-fifth of patients with hypertension have CKD. The high prevalence justifies longitudinal follow-up in order to evaluate whether intensified cardiovascular risk management is beneficial in this primary care population.