Diabetes and obesity among patients with serious mental illness are common. Use of second-generation antipsychotics compounds risk, and widely prevalent unhealthy behaviors further contribute to negative outcomes. This column describes Targeted Training in Illness Management, a group-based psychosocial treatment that blends psychoeducation, problem identification, goal setting, and behavioral modeling and reinforcement. The intervention has been adapted to the primary care setting and is targeted at individuals with serious mental illness and diabetes. A key feature of the intervention is the use of peer educators with serious mental illness and diabetes to teach and model self-management. Promising results from a 16-week trial are reported.