Objective.Spondyloarthritis (SpA) is among the most frequent extraintestinal manifestations of inflammatory bowel diseases (IBD). In this study, we aimed to validate the DETection of Arthritis in Inflammatory boweL diseases (DETAIL) questionnaire in a multicenter cohort of patients with IBD enrolled at 11 gastroenterology units.Methods.From October 2018 to March 2019, consecutive adult patients with IBD, either Crohn disease or ulcerative colitis, independently filled out the DETAIL questionnaire in the outpatient waiting room. Within 2 weeks a blinded rheumatologist assessed all the patients, irrespective of the DETAIL results, and classified them to be affected or not by SpA. The performance of the questions was evaluated through Bayesian analysis.Results.Overall, 418 patients with IBD filled out the DETAIL questionnaire. Upon rheumatological evaluation, 102 (24.4%) patients received a diagnosis of SpA. Of the 6 questions, the best performances were found in question 6 [positive likelihood ratio (LR)+ 3.77], reporting inflammatory back pain at night, and in question 3 (LR+ 3.31), exploring Achilles enthesitis. The presence of back pain lasting > 3 months (LR+ 2.91), back pain with inflammatory features (LR+ 2.55), and a history of dactylitis (LR+ 2.55), also showed a fairly good performance, whereas a history of peripheral synovitis was slightly worse (LR+ 2.16). The combination of at least 3 questions answered affirmatively yielded a posttest probability of SpA of 80% or more. The presence of alternative diagnoses, such as osteoarthritis or fibromyalgia, represented a minor confounder.Conclusion.The DETAIL questionnaire is a useful tool for the early detection of SpA in IBD.