Adolescents with Type 1 Diabetes are at an elevated risk for reduced self-care and imbalanced blood sugar rates with long-term medical consequences. Despite the medical concern, there is a shortage of effective parenting-based interventions for this condition. This pilot study aimed to evaluate the applicability and effectiveness of a New Authority (NA) training for parents of adolescents with imbalanced Type 1 Diabetes. The NA approach teaches parents to improve their involvement and supervision, while reducing parental coercion and parent-child conflict. Thirty-six families of adolescents (age range 12–17) participated in a trial involving three Israeli ambulatory clinics. We collected outcome data from parents and adolescents at four time points: baseline, a 10-week waiting period (serving as control), end of the intervention, and a 10-week follow-up. Measures included glucose level, reported self-care, parental helplessness, parent-child conflict, and parental monitoring of adolescents' illness-management behaviors. All enrolled families completed the treatment. A mixed models analysis of change across time and reporter indicated significant improvement, which was maintained at follow-up in adolescent self-care (F = 3.24), parental monitoring (F = 3.14), and parental helplessness (F = 10.76). Parents, but not youth, reported improvements in parent-child conflict (F = 6.71). Adolescents' glucose levels increased during the waiting period, but declined after treatment, remaining stable at follow-up. The lack of dropout suggested high acceptability for parents. The study provides initial support to NA parent training's efficacy in improving parental helplessness and monitoring, family relations, and medical care in adolescents with Type 1 Diabetes. Additional research involving a randomized clinical trial (RCT) is needed to further validate the effectiveness of the intervention. Trial registration: ClinicalTrials.gov identifier: NCT02093676. Date of registration: March 21st, 2014. Highlights: There is a decline in diabetes self-care during the transition to adolescence that parallels with parental difficulty to supervise the youth's diabetes self-care. As a result, for many adolescents, diabetes is difficult to manage, with harsh consequences for their health. In this study we developed and piloted a new protocol for families of adolescents with Type 1 Diabetes. Treatment is based on the New Authority principles. Parents learn to improve parental presence and supervision while reducing coercive and escalating parent-child interactions. The results of the pilot study suggested high acceptability of the intervention to parents and medical teams. The results indicated improvement in the youth's reported self-care, parental monitoring of the diabetes and in parental helplessness along with reduction in parental reported family conflict. The New Authority intervention may be an effective psychosocial intervention for improving self-care and family interactions of adolescents with Type 1 Diabetes. [ABSTRACT FROM AUTHOR]