Practicing physicians as well as diabetes specialists are confronted with the often-frustrating experience of dealing with patients with poorly controlled diabetes. It is not always obvious why these patients fail to improve. The aims of this study were two-fold: (a). to determine if the interdisciplinary approach offered by the Western Negev Mobile Clinic Diabetes Program (WNMDCP) is of benefit in patients with poorly controlled type 2 diabetes and (b). to more fully characterize patients refractory to treatment. Two primary-care clinics of the Western Negev were randomly selected as control and intervention. All patients from both clinics with hemoglobin (HbA(1C)) >or=10% (tested during June-July 2000) were studied for 6 months. Patients from the control clinic continued the usual treatment. Patients from the intervention clinic received the interdisciplinary approach offered by WNMCDP. The rate of improvement of diabetes control, measured as a decrease in HbA(1C) values of at least 0.5%, and compliance to treatment were determined. Overall, 48 of 258 patients in the intervention clinic and 34 of 179 patients in the control clinic met the inclusion criteria. At the 6-month follow-up, we observed significant improvements in plasma glucose (-1.5 mmol/l; p=0.003) and HbA(1C) (-1.8%; p=0.00001) in the intervention group but not in the control group. The compliance and response rates were 85% and 71% for the intervention group and 32% and 35% for the control group, respectively. Patients from the intervention clinic showed significant improvement in the endpoints compared to patients from the control clinic. More than 70% of patients with poorly controlled diabetes mellitus responded to the interdisciplinary treatment approach offered by WNMDCP. The group of non-responders comprised patients with poor compliance (15%) and those with serious concomitant diseases or limitations of mobility.