A cross-sectional multicentre study was conducted in 165 French diabetic children aged 7-13 y and their parents. A standardized scale (FACES III) was used to determine if family cohesion and adaptability (i) differed in diabetic children's families, as compared to other families; (ii) were related to an adherence measure; or (iii) were related to metabolic control. More diabetic families than comparison families fell into the categories of disengaged with low levels of cohesion, and rigid with low levels of adaptability. Scores of cohesion and adaptability were significantly and positively correlated with both children's and parents' adherence scores, but not with HbA1c levels. Children whose families were characterized as rigidly disengaged had a significantly greater number of hypoglycaemias and six times as many episodes of ketoacidosis than the other diabetic children. Not only in adolescents, but also in families of diabetic children, family-centred interventions are needed to improve compliance and to prevent acute metabolic complications.