Background: Idiopathic thrombocytopaenic purpura [ITP] is an acquired haematological disorder with an incidence of 1–6 per 100 00/year. ITP and inflammatory bowel disease [IBD] comorbidity has been reported in the literature, but insights regarding the course, outcome and optimal management are limited by its rarity. The current study aimed to evaluate the clinical presentation and outcome of ITP in patients with IBD. Methods: This multicentre retrospective case series was performed as part of the ECCO Collaborative Network of Exceptionally Rare case reports [CONFER] project. Cases of patients with ITP and IBD were collected by participating investigators. Clinical data were recorded in a standardized collection form. Results: This report includes 32 patients with concurrent ITP and IBD: ten were females, and the median age was 32.0 years (interquartile range [IQR] 20.5–39.5). Fourteen patients had a diagnosis of Crohn’s disease [CD] and the other 18 ulcerative colitis [UC]. The diagnosis of IBD preceded the ITP in 26 patients (median time between diagnoses was 7.0 years [IQR, 1.5–9.5]). Among those patients, 17 were in clinical remission at ITP diagnosis. Thirteen patients were treated with mesalamine, four with oral corticosteroids, one with rectal corticosteroids, two with azathioprine and five with anti-tumour necrosis factor agents. The median platelet count was 35 000/microliter [IQR, 10 000–70 000]. Eight patients had rectal bleeding, 13 had skin purpura, three had epistaxis, six had mucosal petechiae and 13 were asymptomatic. Regarding ITP treatment, 19 were treated with corticosteroids, one with anti-RhD immunoglobulin, 12 with intravenous immunoglobulins [IVIGs], four with thrombopoietin, three with rituximab and six patients eventually required splenectomy. Ten patients needed no treatment directed to the ITP. Three patients required colectomy during long-term follow-up, due to IBD or cancer but not to massive bleeding as a complication of ITP. One of eight patients who presented with rectal bleeding required splenectomy, and none required urgent colectomy. Two patients died during the follow-up, one of them due to bleeding complications located in the upper gastrointestinal tract. Median follow-up time was 6.5 years [IQR, 3–10]. With long-term follow-up, all patients had platelet counts above 50 000/microliter, and 24 were in IBD clinical remission. Conclusion: Most ITP cases in this series occurred after the IBD diagnosis and responded well to regular ITP treatment. The course of the ITP in the IBD patients followed an expected course, including response to medical therapy and low rates of splenectomy.