A multicentre controlled randomized education study was performed to evaluate an education programme for insulin-treated diabetic patients. The main objective of the education programme, which took place on an out-patient basis, was to improve the level of self-care of the participants. Fifteen randomly recruited hospitals (558 patients) were equally divided into three groups: two experimental groups who completed the programme under the guidance of a health care professional or a fellow patient, and a control group. Patients in the experimental group were evaluated four times and those in the control group twice, with an intervening period of 6 to 7 months. The effect of the programme on metabolic control, quality of life, and costs of therapy was assessed. No significant effect of education of any one of these variables could be found.(ABSTRACT TRUNCATED AT 250 WORDS)