To ascertain to what extent metabolic imbalance of diabetes during adolescence is associated with inconsistency in daily care, psychologic development, or the family system we interviewed a group of 31 diabetics aged 13-16 years and their parents. Depression was the most significant clinical finding among the psychologic characteristics, being a severe symptom in 16% of the diabetics and 5% of their age-matched controls. Two-thirds of the parents reported having experienced considerable turmoil at the onset of their child's disease, and 40% of the mothers still reported continuous concern about the child's well-being. More than two-thirds of all the parents (71%) reported that child's sickness had not changed the relationship between the parents at all. Of the main categories, glycaemic imbalance was most closely associated with inadequate social functioning, less with psychologic problems on the part of the adolescent, and not at all with strict glucose monitoring, physical exercise, or problems in interparental relationships. In conclusion. in the case of patients with poor glycaemic control it seems to be important to make separate evaluations of the family system and its functioning and individual psychologic development to focus rehabilitative work on the main issue.