Objective: To assess whether knowledge or psychosocial and glycemic benefits of a diabetes education program are enhanced by a support group for older patients. Design: A partially randomized controlled trial involving two groups of patients: Group A, subjects who received an education program followed by 18 months of support group sessions; Group B, only the diabetes education program. A third convenience sample, Group C, received neither intervention. Groups A and B were assessed before and immediately after the education program, and all groups were assessed 2 years after the education program. Setting: Diabetes clinic at a Veterans Affairs Medical Center. Patients: All subjects were male (mean age 68 +/- 1.3 years, range = 57-82 years; duration of diabetes 10 +/- 2 years, range 3-16). Sample sizes were 11 in Group A, 13 in Group B, and 8 in Group C. Intervention: The education program consisted of six weekly sessions covering aspects of diabetes self-care. The support group consisted of 18 monthly sessions for continuing education, discussion, and structured social activities. Outcome Measures: Diabetes knowledge, psychosocial factors (self-care-related quality of life, stress, family involvement in care, and social involvement), depression, and glycemic control. Results: Group A scored better (at least P < 0.05) on knowledge, quality of life, and depression than the other groups. Groups A and B showed less stress, greater family involvement, better glycemic control, but less involvement in social activities than Group C. Conclusion: Diabetes education programs can have long term benefits on knowledge, psychosocial functioning, and glycemic control for older diabetic patients. The addition of support groups enhances diabetes knowledge and psychosocial functioning.