Background:The effectiveness of ustekinumab in patients with refractory Crohn’s disease (CD) has been investigated in several real-world studies. However, very few data concerning the real-life experience in Italy have been reported. Therefore, this study assessed the effectiveness of ustekinumab in a large cohort of Italian patients with refractory CD.Methods:All patients who had started on ustekinumab after failure of or intolerance to antitumour necrosis factor-α (TNF-α) treatment at five tertiary centres between November 2018 and February 2020 were retrospectively enrolled. The coprimary outcome was corticosteroid-free clinical remission, defined as a Harvey–Bradshaw Index (HBI) score of ⩽4, at weeks 26 and 52. The secondary outcomes were changes in the HBI and C-reactive protein (CRP) values at weeks 8, 26, and 52 from baseline and the normalization of CRP in patients with initially abnormal values.Results:Totally, 140 patients who had previously received at least one anti-TNF-α agent were enrolled; 40.0% received two anti-TNF-α agents and 20.0% received vedolizumab. At baseline, 108 patients (77.1%) had HBI scores of >4; of these, 56.5% and 58.3% achieved corticosteroid-free clinical remission at weeks 26 and 52, respectively. Significant decreases in HBI and CRP values were observed at weeks 8, 26, and 52 in the entire study cohort (all p < 0.0001). The CRP values were normalized in 34.9%, 37.8%, and 49.3% of the patients by weeks 8, 26, and 52, respectively. The baseline HBI score of ⩾8 was a negative predictor of corticosteroid-free clinical remission at week 52 (odds ratio: 0.21, 95% confidence interval: 0.08–0.56, p = 0.002). The probability of remaining on ustekinumab after 52 weeks was 92.1%. Eleven (7.9%) patients discontinued ustekinumab (three for adverse events).Conclusion:Our study findings confirm the effectiveness and safety of ustekinumab in patients with CD after failure of or intolerance to anti-TNF-α therapy.