Patients with the metabolic syndrome are at an increased risk of cardiovascular disease and might require intensive lipid therapy. Many patients remain at the starting dose of lipid therapy and might not be titrated up to a higher dose. The present double-blind, randomized, 6-week study assessed the lipid-lowering efficacy of ezetimibe/simvastatin 10/20 mg versus atorvastatin 10 or 20 mg, and ezetimibe/simvastatin 10/40 mg versus atorvastatin 40 mg in 1,128 patients with hypercholesterolemia and the metabolic syndrome. The primary end point was the percentage of change from baseline in low-density lipoprotein (LDL) cholesterol. Additional end points included changes in other lipids, lipoprotein ratios, high-sensitivity C-reactive protein, and attainment of prespecified lipid levels. Significantly greater improvements in the levels of LDL cholesterol, non-high-density lipoprotein cholesterol, apolipoprotein B, and lipid/lipoprotein ratios resulted with ezetimibe/simvastatin compared with atorvastatin at all specified dose comparisons (p <0.001). The attainment of prespecified LDL cholesterol and non-high-density lipoprotein cholesterol levels was also significantly greater with ezetimibe/simvastatin than with atorvastatin at all dose comparisons (p <0.05). High-density lipoprotein cholesterol increases were significantly greater with ezetimibe/simvastatin 10/20 mg than with atorvastatin 10 mg (p <0.05) and ezetimibe/simvastatin 10/40 mg than with atorvastatin 40 mg (p <0.01). The changes in triglycerides, very low-density lipoprotein cholesterol, and high-sensitivity C-reactive protein were similar for both treatments. The incidence of liver, muscle, and gastrointestinal-, hepatitis- and allergic reaction/rash-related adverse events were low and generally similar to those in previous studies of ezetimibe/simvastatin and/or atorvastatin. In conclusion, ezetimibe/simvastatin was more likely to result in lipid treatment end points than atorvastatin and was generally well tolerated at the doses compared in our patients.