There is a pressing need for research on behavioral interventions that are capable of being translated into practice for the self management and care of diabetes and other chronic illnesses. To date, the vast majority of diabetes self-management research has been conducted in academic settings and has not addressed real world application issues or the challenges and context of primary care practice. It is well documented that preventive care provided to diabetes patients is supoptimal, even with the distribution of care guidelines, and that mot patients are in need of assistance with behavior change, and especially with maintenance of healthful dietary and physical activity practices. Based upon our previous research and clinical experience, this competing renewal proposal will address these issues by refining and experimentally evaluating a practical, computer-assisted behavior change intervention to facilitate dietary and physical activity practices, and to help patients and providers to engage to recommended preventative practices for diabetes. Three hundred-fifty type 2 diabetes patients from 24 different primary care providers will be randomly assigned to either usual care or to a brief computer-assisted behavioral intervention. The intervention will also include several innovative components to increase linkage and integration with the patient's primary care provider. Following 2 months of intervention, participants will again be randomized to receive either usual care follow-up or a social-ecologic theory based maintenance intervention to increase use of social environmental support resources. Evaluation will be comprehensive and based upon the RE-AIM model dimensions of reach, effectiveness, adoption, implementation, and maintenance. Key outcomes will include behavioral (multiple dietary and physical activity targets), performance of recommended preventive practices, physiologic (HbA1c and lipids) and patient quality of life and satisfaction measures. The results of such a trial, conducted with a representative sample of primary care patients from heterogeneous providers, and emphasizing both internal and external validity criteria, has important implications both for the science of behavior change and for guiding research to practice innovations.