To increase Chlamydia trachomatis screening in adolescents 15-19 years of age from 7.8% to 15% following a 6-week implementation of universal chlamydia screening at three paediatric primary care (PPC) sites. Pre-implementation (1 January 2022-19 October 2022) and post-implementation (20 October 2022-1 June 2023) screening rates were tracked through run charts and compared via Chi-square testing. Universal opt-out chlamydia screening with universal urine collection for 15- to 19-year-old was implemented at well visits, along with patient and staff education, and sexually transmitted infection treatment protocols. Chlamydia trachomatis screening increased from 7.8% to 34.1% with implementation of universal opt-out chlamydia screening. Proportions of patients screened increased significantly among White individuals, males and privately insured individuals. A universal C. trachomatis screening project can be feasibly implemented in pediatric primary care and successfully increase adolescent chlamydia screening rates. Implementing a universal opt-out C. trachomatis screening project is feasible in PPC and can help achieve the public health goal of chlamydia identification and treatment. These findings will be impactful for both paediatric primary care and adolescent patients. The universal, opt-out C. trachomatis screening approach facilitated screening increases, improved equity in screening and led to increased case detection and treatment which has vast significance for those patients. This manuscript is submitted using the SQUIRE 2.0 guidelines for quality improvement reporting. Patient contribution included de-identified data collection of chlamydia screening rates of eligible adolescents 15-19 years old who attended routine well visits at the three PPC locations. The data were reviewed on a dashboard, then stratified by race, ethnicity, payor and sex assigned at birth.