This study examined the effects of sociodemographic variables such as ethnicity, socioeconomic status (SES), and family structure on disease control in 58 children with diabetes stratified by ethnicity and SES. Three dependent variables were chosen to evaluate the disease control of the study participants, including HbA1 values averaged over the year prior to study participation, number of hospitalizations, and number of hypoglycaemic blackouts. SES and family structure, but not ethnicity, were the primary risk factors to disease control. Children from low SES families were in poorer glycaemic control (mean HbA1 = 12.6%) and experienced more episodes of hypoglycaemia-related loss of consciousness (mean = 0.5 per patient) than did children from middle income families (mean HbA1 = 10.4%; mean blackouts = 0.1 per patient). In addition, children from middle-class, two-parent families were in better metabolic control than all other groups. These results indicate that it may not be ethnicity per se, but other factors that often covary with ethnic status, that may pose a risk to the disease status of children and adolescents with diabetes.