The Diabetes Prevention Program (DPP) demonstrated that an intensive lifestyle intervention resulting in modest weight loss and increased physical activity can delay or prevent the development of type 2 diabetes in those at increased risk for the disease. The lifestyle program used, however, was not designed for delivery on a public health scale. Successful community translation of the DPP's findings will require close collaboration with an established community organization committed to improving community health and experienced in implementing sustainable health and wellness programs. With exceptional reach into diverse U.S. communities, the YMCA may be an ideal community partner. We have been collaborating with the YMCA organization for over a year to design a robust recruitment and implementation model that is sensitive to the unique needs and resources of a community organization. We now propose to evaluate if a group-based adaptation of the DPP lifestyle intervention can be successfully implemented by YMCA staff, in YMCA facilities. We have designed this study to develop preliminary data about the reach, effectiveness, and consistent implementation of the DPP lifestyle intervention in this context. This pilot study has two primary aims: 1) to demonstrate the extent to which YMCA staff trained by DPP study personnel can administer a group-based adaptation of the DPP lifestyle intervention in a fashion consistent with DPP intervention protocols, and 2) to evaluate if the intervention program delivered by the YMCA results in changes in body mass, physical activity, and dietary intake that are consistent with a level found to be associated with diabetes risk reduction during the DPP trial. We will also collect valuable data about the feasibility and reach of a selective, community-based marketing and screening approach for recruiting program participants. In combination, these data will enable us to design and conduct a larger, future 3-year trial focusing on the effectiveness and sustainability of community DPP translation in multiple YMCA settings.