BACKGROUND AND PURPOSE: There have been few reports on the efficacy and safety of statins in the Asian population. The study objectives were to compare the efficacy and safety of atorvastatin and simvastatin in Asian people. MATERIALS AND METHODS: This was a 16-week, double-blind, double-dummy, randomized, multicenter study involving eight medical centers in six Asian countries or areas. After a 6-week, diet-controlled, placebo lead-in period, 157 patients with low-density lipoprotein cholesterol (LDL-C) of between 160 and 250 mg/dL and serum triglyceride (TG) of less than 400 mg/dL were randomized to receive 10 mg of either atorvastatin (n = 79) or simvastatin (n = 78). After 8 weeks of treatment, all patients had the dose of study medication increased to 20 mg, irrespective of LDL-C concentration. Data obtained by monitoring lipid profiles, adverse events, and laboratory tests during the 16 weeks of study were used to assess the efficacy and safety of both treatments. RESULTS: After 8 weeks of treatment, LDL-C concentrations were reduced by 42.5% from baseline in patients receiving atorvastatin and 34.8% in those receiving simvastatin (p = 0.0006). Patients treated with atorvastatin also had a significantly greater reduction in very-low-density lipoprotein cholesterol (VLDL-C), TG, and total cholesterol (TC) after 8 weeks of treatment. The significantly greater reductions in LDL-C, VLDL-C, TG, and TC from baseline achieved with atorvastatin were still observed after an additional 8 weeks of treatment with 20 mg study medication. Both drugs increased high-density lipoprotein cholesterol (HDL-C) concentrations after 16 weeks of treatment, with no significant difference between the two treatments. After 16 weeks of treatment, 93% of atorvastatin and 85% of simvastatin patients had achieved their National Cholesterol Education Program LDL-C goals. No deaths occurred in the study population and the incidence of treatment-emergent adverse events was the same in the two groups (28%). Only one patient who was treated with simvastatin had a transaminase or creatine phosphokinase concentration that was more than three-fold the upper limit of normal. CONCLUSIONS: Asian people with primary hypercholesterolemia treated with atorvastatin had lower LDL-C, VLDL-C, TG, and TC after 8 weeks and 16 weeks of treatment than those treated with simvastatin. Both drugs demonstrated acceptable safety profiles.