Background Biologically naïve patients with inflammatory bowel disease treated with vedolizumab (VDZ) are largely underrepresented in real-world cohorts. A multi-centre, observational cohort study was performed on the effectiveness and safety of VDZ in biologically naïve subjects with Crohn’s disease (CD) and ulcerative colitis (UC). Methods Data of consecutive biologically naïve patients with CD and UC treated with VDZ from July 2016 to December 2019 were extracted from the cohort of the Sicilian Network for Inflammatory Bowel Disease. Results A total of 172 consecutive patients (CD: N = 88; UC: N = 84; median age 66.0 years) were included, with a median follow-up of 58.8 weeks. After 14 weeks, a clinical response was reported in 68.2% of patients with CD and 67.9% of patients with UC treated with VDZ, including 45.5% patients in the CD group and 46.4% patients in the UC group who achieved steroid-free remission. After 52 weeks, a clinical response was reported in 77.4% of CD and in 73.8% of UC patients treated with VDZ, including 59.7% patients in the CD group and 60.7% patients in the UC group who achieved steroid-free remission. Conclusions This study demonstrates the effectiveness and safety of VDZ as a first-line biological, particularly among elderly patients.