There is a critical need for health care transition HCT services and health-related independence HRI for youth with ASD. Existing HCT measurement tools fail to address youth and caregiver perspectives and no existing measurement tools examine HRI among youth with ASD. In Aim 1 of this study, we explored HCT and HRI experiences and needs of youth with ASD and their caregivers utilizing qualitative methods including 3 focus groups with caregivers and individual interviews with 27 youth. We identified major themes including caregiver stress, relationships, health challenges, financial, safety, workschool, medication management, transition to adult doctor, and self-care. Within Aim 2a of the study we utilized the themes from Aim 1 and experts in the field to develop an ASD-specific HRI outcome measure. The HRI measure covers 8 domains. The individual items and response options were evaluated by experts in the field, caregivers and youth with ASD and revised based on their recommendations. Cognitive interviewing and full-scale pretesting were then conducted to examine the validity, appropriateness, and user-friendliness of the measure. Within Aim 2b, the HRI measure along with established HCT measures were administer to a national sample of 510 caregivers to better understand HCT, HRI, and predictors of success. Exploratory Factor Analysis was conducted to examine the HRI items and develop independent and reflective constructs and a meaningful total score. The final HRI measure included 5 constructs and was shown to be valid.