Aims: The continuing growth of the population with end-stage renal disease (ESRD) in the past two decades has been recognized as a global health burden. In 2002, a definition of chronic kidney disease (CKD) was introduced and different categories of CKD have been reported in the general population. In this study, we examined the prevalence of CKD in primary health care in Germany. Subjects and methods: From 2004 to 2007 the prevalence of CKD was estimated in the Diabetes Cardiovascular Risk-Evaluation Targets and Essential Data for Commitment of Treatment (DETECT) study using the Simplified Modification of Diet in Renal Disease (MDRD) and the CKD Epidemiology Collaboration (CKD-EPI) equations. A sample of 4,080 subjects were analysed with detailed laboratory and comorbidity assessment from 851 primary care centres across Germany. Results: The prevalence of CKD (≤60 ml/min/1.73 m²) was 27.9 % estimated by CKD-EPI equation (MDRD eGFR 36.1 %) and the prevalence of CKD increased with age and during follow-up. The overall decline in eGFR per year was −1.83 ml/min/year (CKD-EPI). Women have shown a higher decline in eGFR than men. The prevalence of CKD was highest in coronary artery disease patients, followed by diabetes mellitus and arterial hypertension. Individuals with diabetes mellitus have shown the highest progress developing CKD. Conclusion: In this representative sample of patients seeking medical advice in primary care, the prevalence of impaired kidney function was almost one third. Given the therapeutic implications, our results call for focused measures to increase the awareness of CKD in primary care.