The National Cholesterol Education Program Adult Treatment Panel III (NCEP ATPIII) was updated in 2002. The effects of the revised guidelines on lipid profile control in clinical setting are yet to be determined. OBJECTIVE: To investigate the cost-effectiveness of statins in patients with high risk for coronary heart disease (CHD) from the perspective of a public health organization. METHODS: A retrospective cohort study was conducted at the outpatient clinics of a teaching hospital in Hong Kong. Statins were only prescribed to those patients with a 10-year CHD risk > 20 % or CHD risk equivalent per hospital policy. Patients newly started on atorvastatin or simvastatin from 1 October to 31 December 2002; with documented baseline lipid profile and at least one lipid profile measurement done before March 31, 2003 were identified. Costs per member per month (PMPM) was estimated from the costs of drug, clinic visit and lipid profile tests. Clinical outcomes assessed were low-density lipoprotein (LDL) reduction and the rate of target LDL achieved per NCEP ATPIII. Cost-effectiveness ratios were calculated from PMPM and rate of target LDL achieved. RESULTS: The medical records of 56 patients were reviewed. Nineteen patients were started on atorvastatin while 37 patients were started on simvastatin. Mean PMPM cost of atorvastatin was HK$700 ± 199 (1 USD=7.8 HKD); and that of simvastatin was HK$856 ± 476 (p=0.092). Average LDL reduction by atorvastatin was 1.9 ± 0.8 mmol/L; and that by simvastatin was 1.3 ± 0.9 mmol/L (p=0.038). Rate of goal achieved was 68% for atorvastatin and 62% for simvastatin (p=0.651). The cost (per patient per month) per patient achieved target LDL for atorvastatin and simvastatin were HK$1023.78 and HK$1376.41, respectively. CONCLUSIONS: Atorvastatin appears to be more cost-effective than simvastatin as a lipid-lowering monotherapy in high CHD risk patients, with lower cost and improved outcomes.