Two studies compared the effectiveness of a community-based, behavioral group program versus an individual patient-education program with low-income diabetic and hypertensive patients, respectively. The dependent variables measured patients' knowledge, disease management skills, and clinical outcomes. Patients in the group programs demonstrated greater gains in knowledge and disease management skills than did the control patients. However, there was no clinically significant change in weight, blood pressure, or urinalysis results for any group of patients. The data suggest that group management is an effective mechanism for patient education but is not sufficiently reinforcing to induce change of habits, particularly when there are competing sources of reinforcement within the community.