We report a prospective, nationwide cohort evaluating the safety and effectiveness of CT-P13.A structured database was used to record serious adverse events (SAEs), clinical remission/response, inflammatory biomarkers (CRP and calprotectin), and endoscopic findings.Eight hundred ten patients with inflammatory bowel disease (IBD) (452 Crohn’s disease [CD]) were enrolled. Four hundred fifty-nine patients were naïve to anti-TNFα (group A), 196 had a previous exposure (group B), and the remaining 155 were switched to CT-P13 (group C). All patients were included in the safety evaluation with a mean follow-up of 345 ± 215 days and a total number of 6501 infusions. One hundred fifty-four SAEs were reported (19\, leading to cessation of the biosimilar in 103 subjects (12.7\. Infusion reactions were 71, leading to cessation of the biosimilar in 53 subjects (6.5\, being significantly more frequent in patients pre-exposed to anti-TNFα (P = 0.017). The efficacy of therapy was calculated in 754 IBD patients, with a mean follow-up of 329 ± 202 days. Forty-eight patients had a primary failure (6.4\, and 188 (25.6\ lost response during follow-up. Six hundred twenty-eight (364 CD) and 360 IBD patients (222 CD) completed the follow-up at 6 and 12 months, respectively. At 12 months, patients without loss of response were 71\ 64\ and 82\% in groups A, B, and C, respectively (log rank P = 0.01). Clinical/endoscopic scores and inflammatory biomarkers dropped significantly in CD and UC patients (P = 0.01 and P \lt; 0.0001) compared with baseline.In this large prospective cohort, no further signals of difference in safety and effectiveness of CT-P13 in IBD has been observed.