Early identification of patients with chronic kidney disease (CKD) may allow health-care systems to implement interventions aimed at decreasing disease progression and eventual morbidity and mortality. Primary care in the United Kingdom is computerized suggesting a separate screening program for CKD may not be necessary because identifying data already populates primary care databases. Our study utilized a data set of 163 demographic, laboratory, diagnosis, and prescription variables from 130 226 adults in the regions of Kent, Manchester, and Surrey. The patients were 18 years of age and older in a 5-year study period culminating in November 2003. Estimated glomerular filtration rate was calculated from the four-variable Modification of Diet in Renal Disease equation using calibrated creatinine levels. A valid creatinine value was recorded in almost 30% of this cohort. The age-standardized prevalence of stage 3-5 CKD was 10.6% for females and 5.8% for males. In these patients, the odds ratio for hypertension was 2.1, for diabetes 1.33, and for cardiovascular disease 1.69. Only 20% of the diabetic people with stage 3-5 CKD had a blood pressure less than or equal to 130/80 mm Hg. The proportion of patients with anemia significantly rose as renal function declined. We suggest that stage 3-5 CKD is easily detected in existing computerized records. The associated comorbidity and management is readily available enabling intervention and targeting of specialist resources.