This study aims to report resource utilisation and annual cost for chronic immune thrombocytopenia (ITP) patients enrolled consecutively and followed for 1 year. A single-centre, single-arm, retrospective 1-year observational cohort study of adult patients with chronic ITP from a French hospital was conducted. Healthcare resource utilisation and mean cost per patient (with 95% confidence intervals) were estimated for the whole group. Patients requiring at least one hospitalisation formed subgroup 1. Patients with the most severe category of disease formed subgroup 2 [defined as hospitalised patients with ≥1 immunoglobulin (IVIg) infusion (usually reserved for those with bleeding score>8)]. Fifty-seven patients (42F/15M) with a mean age of 48 years (SD=19) at ITP diagnosis were studied. Mean platelet count at diagnosis was 28±26×10?/L. Mean duration of ITP was 3.1 years (SD=2); eight patients had undergone splenectomy at baseline. Subgroup 1 included 27 patients who were hospitalised (full hospitalisation, n=23; and/or day hospitalisation, n=8). Of those, 12 patients received at least one IVIg infusion during hospitalisation (subgroup 2). Total mean cost per patient for the 1-year study period was €7,293 (95% CI=3,369-13,584) for the whole group, €15,334 (95% CI=7,876-27,459) for subgroup 1 and €26,581 (95% CI=12,241-50,578) for subgroup 2. IVIg accounted for 33% of costs for subgroup 1 and up to 43% of costs for patients with more severe disease (subgroup 2). Management of adults with chronic ITP is costly in France, especially for patients with severe disease. IVIg use was a major cost driver.