INTRODUCTION: With 17.7% inhabitants aged ≥65 y population of Croatia is old. Decrease of kidney function is a part of ageing process. AIM: The aim of this study was to examine the prevalence of chronic kidney disease and its risk factors in elderly Croatian population for the first time, and also to compare Cockcroft-Gault, MDRD and CKD-EPI formula in elderly. PATIENTS AND METHODS: Study was designed as epidemiological study. 250 patients were recruited in Nursing homes, and 250 in General practice offices in the City of Zagreb, all of them aged ≥65 y. Medical history and short examination were performed. Blood and urine samples were analyzed for serum creatinine, cholesterol, tryglicerids, proteinuria and red blod count. Glomerular filtration rate was calculated using Cockcroft-Gault, MDRD i CKD-EPI formula. RESULTS: There were 80% females and 20% males, average age was 78.2 y. Age structure differed depending on recruitment place, and significant number of participants were aged ≥80. GFR<60 ml/min/1,73 m2 was found in >75%, and GF<45 ml/min/1,73 m2 in 22-42% participants. Only 26% participants were found to have increased serum creatinine level, 18% had proteinuria and 10% anemia. Significant number of participants had unrecognized and/or poorly regulated diabetes, hypertension and hyperlipidemia. BMI ≥25 kg/m2 was found in 69.8%. CONCLUSION: Prevalence of decreased renal function in our population was significantly greater when compared to other published studies performed in elderly. Serum creatinine is not adequate marker to assess renal function in elderly. There is significant number of participants with unrecognized and poorly regulated diabetes, hypertension and hyperlipidemia.