OBJECTIVE—There is conflicting evidence regarding the utility of stress management training in the treatment of diabetes. The few studies that have shown a therapeutic effect of stress management have used time-intensive individual therapy. Unfortunately, widespread use of such interventions is not practical. The aim of the present investigation is to determine whether a cost-effective, group-based stress management training program can improve glucose metabolism in patients with type 2 diabetes and to determine whether a particular subset of patients is more likely to get positive results. RESEARCH DESIGN AND METHODS—Patients with type 2 diabetes were randomized to undergo a five-session group diabetes education program with or without stress management training. Participants (n = 108) were followed for 1 year, during which HbA_1c tests and questionnaires assessing perceived stress, anxiety, and psychological health were administered at regular intervals to evaluate treatment effects. RESULTS—Stress management training was associated with a small (0.5%) but significant reduction in HbA_1c. Compliance with the treatment regimen decreased over time but was similar to that seen in patients receiving stress management for other reasons in the clinic. Trait anxiety (a measure of stable individual differences in anxiety proneness) did not predict response to treatment, showing that highly anxious patients did not derive more benefit from training. CONCLUSIONS—The current results indicate that a cost-effective, group stress management program in a “real-world” setting can result in clinically significant benefits for patients with type 2 diabetes.