Background/Aims: Both high-dose atorvastatin and rosuvastatin have been shown to reduce contrast-induced acute kidney injury (AKI) occurrence and improve clinical outcomes in high-risk coronary patients undergoing angiographic procedures. However, there is a lack of head-to-head comparative studies on the effects of atorvastatin or rosuvastatin administered upon hospital admission in statin-naive patients with non-ST segment elevation acute coronary syndrome (NSTE-ACS). Methods: In this open-label, noninferiority study, we compared changes in renal function in 709 NSTE-ACS patients randomized to atorvastatin (80 mg upon admission followed by 40 mg/day) or rosuvastatin (40 mg upon admission followed by 20 mg/day). The primary end point was AKI (increase in serum creatinine ≥0.5 mg/dL or ≥25% above baseline within 72 h). Worsening renal function (WRF) (decrease of ≥25% in the glomerular filtration rate from baseline to 30 days), 30-day major adverse cardiovascular events, and 12-month myocardial infarction (MI) or death were also evaluated. Results: The AKI incidence was similar in the 2 groups (i.e., 8.2% with rosuvastatin and 7.6% with atorvastatin; absolute risk difference = 0.54; 90% CI –3.9 to 2.8), satisfying the noninferiority criteria. WRF occurred in 53 (7.5%) patients, 19 (34%) of whom had developed AKI. The rates of WRF and adverse events at 30 days and at 12 months did not differ significantly between the 2 groups. Both AKI and WRF were found to be closely associated with the 12-month cardiovascular outcome irrespectively of statin choice. Conclusions: High-dose rosuvastatin or atorvastatin started upon hospital admission led to similar rates of AKI, 30-day renal function changes, and 12-month death or MI in NSTE-ACS patients who underwent an early invasive strategy (clinical trial registration: https://www.clinicaltrials.gov; unique identifier: NCT01870804).