BACKGROUND: Vedolizumab is approved for moderate to severe Crohn's disease (CD) and ulcerative colitis (UC). We present prospective, 1-year data of the real-world effectiveness and safety of vedolizumab in inflammatory bowel disease. METHODS: Consecutive patients receiving vedolizumab for treatment of UC or CD with at least 14 weeks of follow-up, regardless of outcome, were included. Patients had clinical activity scores (Harvey-Bradshaw Index [HBI] or Simple Clinical Colitis Activity Index [SCCAI]) and inflammatory markers prospectively measured at baseline and weeks 14, 30, and 52. Clinical response was defined as a reduction ≥3 in HBI or SCCAI, clinical remission as HBI ≤4 or SCCAI ≤2, steroid-free remission as clinical remission without the need for corticosteroids, and mucosal healing (assessed at 6 months) as a Mayo endoscopic subscore of 0 or 1 or CD-SES <3. RESULTS: A total of 132 patients were included: 61 (45%) male, 94 (71%) with CD, 42 (29%) with UC; 22% and 34% of CD and UC patients, respectively, achieved steroid-free remission by week 14. This increased to 31% in CD patients and plateaued at 35% in UC patients at 12 months. Increasing remission rates to 6 months were seen in patients with CD, but minimal improvements after 3 months of therapy occurred in those with UC. Mucosal healing was achieved in 52% of UC and 30% of CD patients. Most adverse events were minor; 74% remained on vedolizumab at 12 months. CONCLUSIONS: In this real-world study, vedolizumab demonstrated similar efficacy and safety seen in pivotal trials, with sustained clinical response in the majority of patients. Similar rates of response were seen in UC and CD patients. 10.1093/ibd/izx067_video1izx067_Video5754037470001.