BACKGROUND: Statins can significantly improve the lipid profile and reduce cardiovascular events. However, beneficial effects of statins on renal function are still controversial. PubMed, the Cochrane Central Register of Controlled Trials, Web of Knowledge, and ClinicalTrials.gov Web sites were searched for randomized controlled trials. The selected studies reported renal function during treatment with statins and control. Forty-one studies with a total of 88,523 participants were included in this analysis. Compared with statins, placebo group had significantly decreased estimated glomerular filtration rate (eGFR): the standardized mean difference (SMD) of eGFR in change from baseline was 0.15 (95% confidence interval [CI] 0.07 to 0.23, p = 0.0004) in patients with eGFR >60 ml/min and 0.09 (95% CI 0.01 to 0.17, p = 0.02) in patients with eGFR 30 to 60 ml/min. Compared with placebo, statin group had significantly greater reduction of proteinuria: the SMD of proteinuria in change from baseline was -1.12 (95% CI -1.95 to -0.30, p = 0.008) in patients with urinary protein excretion 30 to 300 mg/day and -0.77 (95% CI -1.35 to -0.18, p = 0.01) in patients with urinary protein excretion > 300 mg/day. eGFR was significantly greater with high-intensity statins than with moderate-intensity statins (SMD 0.12, 95% CI 0.08 to 0.16, p = 0.00001). Placebo group had significantly decreased eGFR for 1 to 3 years (SMD 0.05, 95% CI 0.02 to 0.08, p = 0.003) and >3 years (SMD 0.14, 95% CI 0.04 to 0.25, p = 0.007) of statin therapy. The beneficial effect of statins on renal function may be dosage related and duration dependent. In conclusion, statins appear to decrease the rate of reduction of eGFR and slow the progression of pathologic proteinuria moderately. Copyright © 2014 Elsevier Inc. All rights reserved.