OBJECTIVES: The Joint British Societies (JBS) 2005 guideline on prevention of cardiovascular disease (CVD) advocates prevention in people with established CVD, with diabetes and with CVD risk ³20% over 10 years. This study was designed to establish the number of patients eligible for statin treatment in Scotland under these new guidelines, compared to those previously eligible under the National Service Framework (NSF) for CHD 2000, and estimate the budget impact of treating these additional patients to the JBS 2 optimal total cholesterol (TC) target of <4.0mmol/L. METHODS: Data from the Scottish Health Survey 2003 (mean baseline TC, incidence of CVD and diabetes) were combined with predicted coronary heart disease (CHD) risk estimates and population statistics in an Excel-based model to estimate number of eligible patients. Efficacy data from the STELLAR (Statin Therapies for Elevated Lipid Levels compared Across doses to Rosuvastatin) trial and pack costs from standard sources were used to determine percentage of patients reaching the specified TC target and annual treatment costs for alternative strategies comprising simvastatin 40mg followed by either atorvastatin (20mg, 40mg and 80mg) or rosuvastatin (10mg, 20mg and 40mg). RESULTS: The results using JBS 2, showed 21.3% of the adult population in Scotland is eligible for statin treatment: a total of 881,402 people. Using the NSF, only 12.4% or 513,600 people were eligible, this is an increase of 367,802 (8.9%). The cost of treating these additional patients with the simvastatin/atorvastatin strategy was estimated at £74.4m with 62.9% reaching the TC target of <4.0mmol/L. Treatment with the simvastatin/rosuvastatin strategy was estimated to cost £70.3m with 66.5% of patients reaching this target. CONCLUSIONS: A simvastatin/rosuvastatin strategy is more cost-effective than a simvastatin/atorvastatin strategy at treating newly eligible Scottish patients, with cost savings of £4.1m and an additional 3.6% of patients (13,314) reaching the TC target of <4.0mmol/L.