OBJECTIVES: The English NHS currently has a policy of providing Health Checks to all 40-74 year olds. Administered in primary care they aim to identify patients at risk of a range of diseases, including diabetes and heart disease and facilitate relevant support. Despite initial hypothetical modelling by the Department of Health suggesting the policy would be highly cost-effective, recent clinical evaluations have questioned the policy’s value. This study is the first to use observed data on the effectiveness of the Checks to consider whether they represent a cost-effective use of limited NHS resources. METHODS: Using a publicly available evaluation tool (EConDA) we conducted an analysis of the Checks. The tool evaluates the long term cost and health related outcomes of an obese cohort of patients. The primary focus of the analysis was to establish if the impact of the checks on BMI (a primary risk factor for the diseases described), was sufficient to justify their cost to the UK NHS. A difference in difference analysis was used to achieve this. RESULTS: The results show that the Checks are associated with a reduction in mean BMI of 0.27 (95% CI 0.20 to 0.34), compared to no check. When applied to the EConDA tool, a small but positive QALY gain of 0.05 per participant was observed, coupled with a reduction in disease related costs to the NHS of £170. When the estimated cost per Check (£179) is taken into account we estimate an incremental cost-effectiveness ratio of £900/QALY. CONCLUSIONS: Much of the criticism of the Health Checks has focussed on the relatively small average change in risk factors such as BMI. However, our analysis suggests that the significant health and cost-saving benefits from even a small reduction in mean BMI, and the low costs of the Checks, combine to result in a potentially highly cost-effective policy.