OBJECTIVE: To describe a population-based approach to the identification of individuals at high risk for the development of type 2 diabetes mellitus (DM). STUDY DESIGN: A prospective analysis of the incidence of DM in low- and high-risk groups. PATIENTS AND METHODS: Questions associated with the risk of developing DM were incorporated into a health risk assessment (HRA), and health plan members were invited to complete the HRA as part of worksite health promotion efforts or medical clinic visits. Points were applied to the risk factors for DM, and individual HRA responders were assigned to low- or high-risk groups. A total of 16 427 members completed the HRA. To assess the incidence of new cases of DM, follow-up time was up to 4.8 years (mean, 2.55 years). New-onset DM cases were identified using International Classification of Diseases, Ninth Revision, coding for DM during the timeframe subsequent to HRA completion. RESULTS: The incidence of new DM at the end of the study was 3.5% in the high-risk group and 0.7% in the low-risk group (P < .001). CONCLUSIONS: Identification of individuals at risk for DM using this HRA approach increases by 5-fold the likelihood that the targeted risk reduction efforts will reach the right individuals. This approach allows for resource-efficient targeted intervention efforts designed to reduce the incidence of new DM cases.