Background and Aims: There is a need to evaluate the benefit-risk ratio of current therapies in inflammatory bowel disease (IBD) patients to provide the best quality of care. The primary objective of I-CARE (IBD Cancer and serious infections in Europe) was to assess prospectively safety concerns in IBD, with specific focus on the risk of cancer/lymphoma and serious infections in patients treated with anti-tumor necrosis factor and other biologic monotherapy as well as in combination with immunomodulators. Methods: I-CARE was designed as a European prospective longitudinal observational multicenter cohort study to include patients with a diagnosis of Crohn's disease, ulcerative colitis, or IBD unclassified established at least 3 months prior to enrollment. Results: A total of 10,206 patients were enrolled between March 2016 and April 2019, including 6169 (60.4%) patients with Crohn's disease, 3853 (37.8%) with ulcerative colitis, and 184 (1.8%) with a diagnosis of IBD unclassified. Thirty-two percent of patients were receiving azathioprine/thiopurines, 4.6% 6-mercaptopurine, and 3.2% methotrexate at study entry. At inclusion, 47.3% of patients were treated with an anti-tumor necrosis factor agent, 8.8% with vedolizumab, and 3.4% with ustekinumab. Roughly one-quarter of patients (26.8%) underwent prior IBD-related surgery. Sixty-six percent of patients had been previously treated with systemic steroids. Three percent of patients had a medical history of cancer prior to inclusion and 1.1% had a history of colonic, esophageal, or uterine cervix high-grade dysplasia. Conclusions: I-CARE is an ongoing investigator-initiated observational European prospective cohort study that will provide unique information on the long-term benefits and risks of biological therapies in IBD patients. (EudraCT, Number: 2014-004728-23; ClinicalTrials.gov, Number: NCT02377258).