Statins have been used to prevent contrast-induced nephropathy (CIN). However, the optimal dose of statins is still under controversy. This study aimed to investigate the optimal dose of atorvastatin for the treatment of CIN after carotid artery stenting (CAS). Seventy-six patients receiving selective CAS were randomized to receive 3 different dose of atorvastatin (low dose, 20 mg, n = 30; intermediate dose, 40 mg, n = 24; high dose, 60 mg, n = 22). Preoperatively and on day 3 postoperatively, the levels of serum creatinine, blood urea nitrogen, high-sensitivity C-reactive protein (hs-CRP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and creatine kinase (CK) were measured. Creatinine clearance (Ccr) and CIN incidence were calculated. In patients treated with high-dose atorvastatin, no significant change was observed in levels of serum creatinine (Scr), blood urea nitrogen (BUN), creatinine clearance, and high-sensitivity C-reactive protein after the CAS procedure (P > 0.05). The CIN incidence in the high-dose group (0%) was significantly lower than the low-dose (13.3%) and intermediate (8.3%) groups (P < 0.05). In the high-dose group, levels of alanine aminotransferase, aspartate aminotransferase, and creatine kinase were significantly increased after CAS (P < 0.05). Pretreatment with 40 mg of atorvastatin is both effective and safe in preventing CIN after CAS. Adverse events of the live and heart should be closely monitored during atorvastatin treatment.