Background: Uruguay has implemented a chronic kidney disease (CKD) prevention program. Aims: The objectives of the study are to assess the results of the National Renal Healthcare Program (NRHP). Methods: This study is a cohort study of nondialysis-registered patients from October 2004 to March 2008. We made a comparison between patients under nephrology care (NC) or the care of a primary care physician (PCP; prereferral). In the outcome analysis, the primary endpoint was end-stage renal disease (ESRD) and the secondary endpoints were progression of CKD, compliance with the therapeutic goals and death. ESRD/mortality predictors were determined by Cox analysis. Results: The study comprised 2,219 patients aged 67.4 ± 13.5 years, of whom 52.5% were male, 42.1% hypertensive, 16.9% had diabetic nephropathy, and 61.3 and 21.4% were in CKD stages III and IV, respectively. At baseline, NC patients showed a better control than patients under the care of a PCP: systolic blood pressure ≧160 mm Hg (22.4 vs. 31.1%); total cholesterol <5.8 mmol/l (56.6 vs. 42.5%); and low-density lipoprotein cholesterol <2.9 mmol/l (41.2 vs. 29.1%). Control improved in patients under the care of a PCP according to years of enrollment. Outcome analysis (1,188 patients) showed a significant improvement in targets, with 56% of the patients stabilizing. CKD stage IV, diabetic nephropathy, proteinuria and hypertension increased the risk of ESRD; angiotensin-converting enzyme inhibitors/angiotensin receptor blockers and age <65 years decreased the risk. Conclusions: Our results highlight the best management of CKD patients in both groups and the impact of the NC and renin-angiotensin-aldosterone system blockers.