This 6-week Prospective, Randomized, Open-label Blinded End point (PROBE) study conducted at 12 sites in the United States compared the efficacy and safety of atorvastatin with cerivastatin. In all, 215 hypercholesterolemic patients (low-density lipoprotein [LDL] cholesterol > or = 160 mg/dl [4.14 mmol/L]; triglycerides < or = 400 mg/dl [4.52 mmol/L]) were randomized to receive either atorvastatin 10 mg once daily (n = 108) or cerivastatin 0.3 mg once daily (n = 107). Efficacy was assessed by measuring changes from baseline in LDL cholesterol, total cholesterol, high-density lipoprotein cholesterol, apolipoprotein B, and triglycerides. Atorvastatin produced significantly greater (p < 0.0001) reductions from baseline to week 6 in LDL cholesterol (37.7% vs 30.2%), total cholesterol (27.5% vs 22.2%), and apolipoprotein B (28.6% vs 21.2%), and a significantly greater (p < 0.05) increase from baseline to week 6 in high-density lipoprotein cholesterol (6.8% vs 4.3%) than cerivastatin. Atorvastatin treatment was also associated with a greater percent decrease from baseline to week 6 in triglycerides, with a trend toward statistical significance (p = 0.0982). The percentage of patients that achieved the National Cholesterol Education Program LDL cholesterol goal was greater for those receiving atorvastatin (73%) than for those receiving cerivastatin (66%). The proportion of patients experiencing drug-attributable adverse events, which were mostly mild to moderate and related to the digestive system, was significantly less (p < 0.05) with atorvastatin (5%) than with cerivastatin (14%) treatment. In conclusion, atorvastatin (10 mg/day) is more effective at lowering LDL cholesterol in hypercholesterolemic patients than cerivastatin (0.3 mg/day). Both atorvastatin and cerivastatin are well tolerated, with safety profiles similar to other members of the statin class.