Vedolizumab (VDZ) is a gutselective integrin inhibitor used to treat Crohn's disease (CD) and ulcerative colitis (UC). This retrospective study assessed effectiveness and treatment persistence of VDZ in a Belgian reallife cohort of CD and UC patients. CD and UC patients from 15 Belgian centers, who started VDZ between 01/09/2015 and 31/06/2016 and attended ≥1 visit after the first VDZ infusion, were included. Data were collected before first infusion, at week (W)10, W14 (CD patients only), month (M)6 and last follow-up. Treatment response and remission rates (changes in disease activity scores) and treatment persistence (Kaplan-Meier analysis) were assessed. Of the 348 patients receiving at least one dose of VDZ, 325 (202 CD, 45 biologic-naïve; and 123 UC, 42 biologic-naïve) patients were included in data analyses. At M6, 87.6% (176/201) of CD and 86.1% (105/122) of UC patients were still on VDZ treatment, 75.6% (34/45) and 83.9% (26/31) achieved clinical response, and 66.7% (44/66) and 42.9% (15/35) were in remission. At M6 remission rates was significantly higher while response rates tended to be higher among biologic-naïve versus biologic-failure CD patients. VDZ offers an effective treatment option in real-life settings and treatment effectiveness appears higher in biologic-naïve versus biologic-failure CD patients. (Acta gastroenterol. belg., 2020, 83, 15-23).