OBJECTIVE - To examine the role of parenting style in achieving metabolic control and treatment adherence in adolescents with type 1 diabetes. RESEARCH DESIGN AND METHODS - Parents of 100 adolescents with type 1 diabetes completed assessments of their parenting style and sense of helplessness. Parents and patients rated patient adherence to the treatment regimen. Glycemic control was evaluated by HbA 1cvalues. RESULTS - An authoritative paternal parenting style predicted better glycemic control and adherence in the child; a permissivematernal parenting style predicted poor adherence. A higher sense of helplessness in both parents predicted worse glycemic control and lesser adherence to treatment. Parental sense of helplessness was a significant predictor of diabetes control after correcting for other confounders (patient age, sex, and treatment method). CONCLUSIONS - An authoritative nonhelpless parenting style is associated with better diabetes control in adolescents. Paternal involvement is important in adolescent diabetes management. These results have implications for psychological interventions.