Byline: Claire Abraham, Division of General Pediatrics, Boston Children×s Hospital, Harvard Medical School, Boston, Massachusetts (Dr Abraham); and Department of Pediatrics, Columbia University Irving Medical Center, New York City, New York (Drs Avis, Caddle, Lane, and Friedman).; Emily Avis; Steve Caddle; Mariellen Lane; Suzanne Friedman Abstract BACKGROUND/OBJECTIVE: Phone triage systems are increasingly used by primary care clinics to improve patient satisfaction and direct low-acuity patients to appropriate care settings. Despite the prevalence of telephone triage, the majority of pediatric training programs do not include this practice in their curricula. Our aim was to increase the volume of after-hours patient phone calls per week by 25% and to secondarily reduce "treat and release" emergency department (ED) visits by 5% over the course of a 9-month quality improvement (QI) study. METHODS: A resident-led QI project was conducted from 2017 to 2019 at a mixed faculty-resident pediatric primary care practice providing care for an urban, primarily immigrant, underserved population. Eight Plan-Do-Study-Act cycles were developed on the basis of identified key drivers and included efforts to increase the visibility of the call service to patient families. After-hours calls were tracked and compared with similar practices, and ED visits for the first week of each month were reviewed using the electronic medical record system. RESULTS: After promoting the service via various modalities, the number of after-hours calls increased by 30%, from an average of 6.5 calls per week to 8.5. Treat and release ED visits decreased by 6%, from a baseline of 64.3 to 60.3 visits per week. CONCLUSIONS: The increased patient awareness of and availability of a reliable after-hours call service in pediatric practices are promising tools for reducing unnecessary ED visits, leveraging resident direction and implementation to promote the service through varying modalities.