Introduction: A regulatory FDA IDE prospective multi-center clinical trial (G170261-NCT03525808) was performed to evaluate rigorous protocolized management of walled off necrosis (WON) ≥ 6 cm in size with > 30% necrotic material using endoscopic ultrasound (EUS) guided lumen apposing metal stent (LAMS) placement with/without endoscopic necrosectomy. Few studies have examined changes in health related quality of life (HRQOL) before and after endoscopic management for WON. The SF-12 is a validated measure of HRQOL containing 12 items which yield a Mental Components Score (MCS) and a Physical Components Score (PCS). Higher scores correspond to a greater perceived quality of life. Methods: The pre-specified target sample of 40 consecutive eligible patients was enrolled by multiple centers from September 2018 to March 2020. Patients with radiographic WON resolution (as demonstrated by size ≤ 3 cm on CT or MRI) and/or 60 days LAMS indwell time had stent removal followed by an end of study visit 6 months later. SF-12 quality of life questionnaires were completed by patients at baseline, stent removal and at the end of study visit. Results: Mean SF-12 Physical Components Score (PCS) was 27.5±21.1 at baseline, 54.4±19.5 at the time of LAMS removal, and 77.9±22.3 at end of study. Mean SF-12 Mental Components Score (MCS) was 44.9±20.1 at baseline, 64.7±16.5 at the time of LAMS removal, and 79.0±17.2 at end of study. The mean improvement in PCS score from baseline to LAMS removal was 26.0±24.8 (p< 0.0001), with the mean improvement in score from baseline to end of the study being 49.1±29.6 (p< 0.0001). The mean improvement in MCS was 19.6±20.1 from baseline to LAMS removal (p< 0.0001) and 32.0±22.3 from baseline to the end of study (p< 0.0001). The mean improvement from the time of stent removal to the end of study was 25.2±18.0 (PCS, p< 0.0001) and 15.5±18.5 (MCS, p=0.0002) (Figure). Conclusion: These data suggest that patients undergoing protocolized endoscopic necrosectomy for walled-off pancreatic necrosis experience significant improvement in both physical and mental HRQOL. Improvement in the physical score domain appeared to be greater than for the mental score domain. HRQOL indicators continued to improve over a mean follow-up of 180 days.Figure 1.: SF-12 Physical and Mental Components Score.