This cross-sectional, multicenter study investigated the prevalence of chronic kidney disease and associated disorders, in an adult population sample (> 18 years old) attending Primary Care services in Spain. Estimated glomerular filtration rate (Modification Diet in Renal Disease equation) was used for analysis of kidney disease prevalence according to NFK-KDOQI (The National Kidney Foundation-Kidney Disease Outcomes Quality Initiative) stages. Data were collected on serum creatinine, other laboratory parameters blood pressure, and medical history of cardiovascular risk factors or disease (hypertension, dislypidemia, diabetes, congestive heart failure, coronary artery disease, stroke or peripheral arteriopathy) in 7,202 patients attending Primary Care Centers. 47.3% were males, mean age 60,6 +/- 14,3 years, BMI 28.2 +/- 5.3, with 27,6% overweight (27-30 kg/m2) and 32,1% obese (BMI>or=30 kg/m2), The prevalence of cardiovascular risks factors were: absence in 17.3%, one factor 26.9% two 31.2%, and 23.6% presented three or more The frequency of CV risk factors was: hypertension (66.7%), dyslipidemia (48%) and diabetes (31.5%). Congestive heart failure, coronary artery disease, stroke or peripheral vascular disease frequency was lower than 10% The prevalence of eGFR < 60 ml/min x 1.73 m2 was: stage 3 (30-59 ml/min/1.73 m2) 19.7%; stage 4 (15-29 ml/min/1.73 m2) 1.2%; stage 5 no dialysis (GFR < 15 ml/min) 0.4%. This prevalence increased with age in both sexes and 33,7% of patients attending Primary Care services over 70 years presented a eGFR < 60 ml/min. Of the total patients with eGFR < 60 ml/min 37.3% had normal serum creatinine levels. This study documents the substantial prevalence of significantly abnormal renal function among patients at Primary Care level. Early identification and appropriate nephrological management of these patients with renal disease is an important opportunity for an adequate prescription of drugs that interfere with renal function, to delay the progression of renal disease and modify CV risk factors.