Cerebral adrenoleukodystrophy (CALD) is a rare, X-linked, metabolic disease characterized by rapidly progressive inflammatory cerebral demyelination leading to progressive, irreversible loss of neurologic function and death if left untreated. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been shown to have a beneficial effect on clinical indices of disease and long-term survival, but has significant associated risks including graft-versus-host disease (GVHD). This study evaluates the one-year episode costs of allo-HSCT for CALD. This was a retrospective analysis of the U.S. MarketScan Commercial and Medicaid Multi-State databases (2012-2018). CALD allo-HSCT cases were identified by evidence of ≥1 medical claim for allo-HSCT (based on ICD-9-CM procedure codes) AND at least one claim with a specific CALD diagnosis code (ICD-10-CM E71.520) OR at least one claim of either peroxisomal disorder (ICD-9-CM 277.86/ICD-10-CM E71.50) or glucocorticoid deficiency (ICD-9-CM 255.41/ICD-10-CM E27.1). Demographics, resource use, and one-year episode costs (defined as maximum of 365 days post admission date from initial allo-HSCT) were summarized per patient. We identified 14 episodes of allo-HSCT for CALD. Median age at time of transplant was 8 years (mean 10, min 2; all < 16 except one patient age 40). Follow-up time ranged from 6.3 to 56.7 months. GVHD was identified in 85.7% (12/14) of the episodes. Systemic steroids were utilized in 7/11 episodes (drug data missing for 3 patients). Median total episode costs (i.e. amounts reimbursed by insurer) were $588,223 (mean $704,812, range $118,912 – $2,327,603). The initial allo-HSCT inpatient stay accounted for a mean 60.3% of total episode costs (range 13.1% to 89.6%). Many rehospitalizations included GVHD, with some costing > $300,000. Total episode costs for allo-HSCT for the treatment of CALD are substantial, and there is wide variation in costs depending upon the need for rehospitalization, driven, in part, by management of GVHD.