Establishing that mucosal healing (MH) has occurred after therapy is an important treatment goal, and the gold standard is endoscopic evaluation. In UC it is unclear if clinical parameters are adequate. The pediatric ulcerative colitis activity index (PUCAI) has demonstrated good correlations for clinical remission and disease severity, but its role for establishing mucosal healing after therapy has not been validated . The ability to predict mucosal healing may be different for patients in long term remission compared to assessment after obtaining clinical remission. No previous study has prospectively validated the use of PUCAI as a proxy for MH specifically during clinical remission after therapy.