Background and Aims Given the paucity of population-based data on the association between inflammatory bowel diseases [IBD], coeliac disease [CeD], and coeliac autoimmunity [CeA] we aimed to study the associations in a nationwide study. Methods Using health administrative data for all four health maintenance organisations in Israel, covering 98% of the population, we explored the prevalence of CeD in children and adults with IBD versus non-IBD matched controls. CeD was defined by three ICD-9 codes and CeA by positivity for tissue transglutaminase antibodies. Results In total, 34 375 IBD patients (56% Crohn’s disease [CD] and 44% ulcerative colitis [UC]) were compared with 93 603 non-IBD controls. Among IBD patients, 319 [0.93%] had CeD versus 294 [0.31%] non-IBD controls (odds ratio [OR] = 2.97, 95% confidence interval [CI] 2.54-3.48; p Conclusion CeD and CeA are more prevalent in IBD patients, especially in paediatric-onset IBD and in CD. The diagnosis of CeD usually precedes that of IBD. Having CeD is associated with more intensified treatment for IBD.