This paper reports a 5-year follow-up from a study aimed at evaluating whether an intervention which focused on patients' personal understanding of their illness was more effective than conventional diabetes care with regard to metabolic control among patients with type 2 diabetes mellitus (DM2). The study was conducted within Swedish primary health care and included 102 patients (mean age 63 years). At clinic level they were randomised into control or intervention groups. The intervention directed at patients consisted of ten two-hour group sessions over 9 months, focusing on patients' own needs and questions. The mean HbA1c at baseline was 5.71% (S.D. 0.76) in the intervention group and 5.78% (S.D. 0.71) in the control group. At the 5-year follow-up, the mean HbA1c in the intervention group still was 5.71% (S.D. 0.85) while among the controls it had increased to 7.08% (S.D. 1.71). The adjusted difference was 1.37 (p<0.0001). Treatment upgrade, BMI, total cholesterol, HDL, LDL and triglycerides at baseline did not influence the difference in HbA1c. These findings indicate that group sessions in patients with DM2 focusing on patients' personal understanding of their illness are more effective than conventional diabetes care with regard to metabolic control.