Tumor necrosis factor inhibitors (TNFi) are effective treatments for ulcerative colitis (UC). The TNFi certolizumab pegol (CZP) is effective in Crohn’s disease, and an open label (OL) study suggested that CZP is effective for induction of response in UC. Maintenance with CZP in UC has not been studied. This pilot study evaluated CZP effectiveness for maintenance of clinical and endoscopic response in patients (pts) with UC.