Purpose: Significant knowledge gaps regarding outcomes of gender-affirming therapy in transgender (TG) and gender expansive (GE) youth impede an evidence-based approach to these patients. The Gender Wellness Center (GWC) Pediatric Patient Registry was established in 2017 to enable systematic, longitudinal research to describe the physical, mental, and quality-of-life outcomes of these youth.Methods: All TG/GE youth, ages 8–21 years, presenting to the GWC were recruited on site. Ten research questions guided the creation of data fields. The following 131 variables were abstracted from electronic medical records: demographics, weight, height, body mass index, gender identity, sexual orientation, coexisting diagnoses, substance use, Tanner stage, sexual activity, medications, fertility preservation, Gonadotropin Releasing Hormone (GnRH) analog use, hormone therapy, surgery, and related outcomes. Health-related quality of life is assessed using the Child Health Questionnaire-87 for ages <18 and the Short Form-36 for ages 18–21.Results: To date, 139 TG and GE youth (90% white and 93% non-Hispanic), have enrolled in the registry. Average age at enrollment was 17.5 years (±3.1, range: 8–21). Two-thirds of youth identified on the trans masculine spectrum (n=90), 28.8% identified on the trans feminine spectrum (n=40), and 6.5% identified as nonbinary/gender nonconforming (n=9). Nearly, all youth had socially transitioned (n=121, 87.7%) and were medically transitioning (n=123, 89.1%).Conclusion: As one of the first rural-based registries, the GWC Registry has helped to delineate health outcomes attributable to gender-affirming care in a unique patient population of TG/GE youth. Our results will be used to describe treatment outcomes that will contribute to evidence-based guidelines.