Objective To establish the cost effectiveness of nurse led secondary prevention clinics for coronary heart disease based on four years' follow up of a randomised controlled trial. Design Cost effectiveness analysis. Setting 19 general practices in north east Scotland. Participants 1343 patients (673 in intervention group and 670 in control group, as originally randomised) aged under 80 years with a diagnosis of coronary heart disease but without terminal illness or dementia and not housebound. Intervention Nurse led clinics to promote medical and lifestyle components of secondary prevention. Main outcome measures Costs of clinics; overall costs to health service; and cost per life year and per quality adjusted life year QALY) gained, expressed as incremental gain in intervention group compared with control group. Results The cost of the intervention (clinics and drugs) was 136 pound ($254; E195) per patient higher (1998-9 prices) in the intervention group, but the difference in other NHS costs, although lower for the intervention group, was not statistically significant. Overall, 28 fewer deaths occurred in the intervention group leading to a gain in mean life years per patient of 0.110 and of 0.124 QALYs. The incremental cost per life year saved was 11236 and that per QALY was 1097. pound Conclusion Nurse led clinics for the secondary prevention of coronary heart disease in primary care seem to be cost effective compared with most interventions in health care, with the main gains in life years saved.