Risk factor modification to prevent the development of coronary heart disease (CHD) is a rapidly growing concern of physicians interested in disease prevention. Drug treatments to reduce hypertension and hyperlipidaemia are 2 important interventions for CHD primary prevention. The benefits of these interventions have been demonstrated in short term clinical trials by reducing the incidence of stroke and coronary events. While the short term benefits may appear modest, the long term changes in life expectancy and disease morbidity may be substantial for carefully targeted groups of patients. Computer models are therefore increasingly being used to estimate the long term benefits of risk factor modification among selected patients. A review of published CHD models demonstrates that predictions among the different models are usually consistent. Moreover, the results of randomised clinical trials can be accurately forecasted using the CHD Primary Prevention Model.