BACKGROUND: To accurately quantify the costs of care for patients with transfusion-dependent thalassemia (TDT), and to evaluate cost-effectiveness of new treatments, data are required on costs of regular red blood cell (RBC) transfusions. However, no previous studies have evaluated the costs of RBC transfusion specifically in chronically transfused patients. METHODS AND MATERIALS: We performed a time-driven activity-based costing (TDABC) study using a health care provider perspective. This was performed over a 1-month period, capturing every step of the transfusion pathway for patients with TDT at a designated provider of specialist thalassemia services in Australia. Detailed process maps were developed to outline treatments and processes directly related to transfusion. For each process map, detailed data collection, including timing of activities, was performed multiple times to account for variation in practice. Costs associated with RBC transfusion were broken down into fixed, process, and RBC procurement costs. RESULTS: The total per-unit cost was US$695.59 (95% confidence interval, US$694.45-US$696.73). Approximately 40% of cost was for procurement of the RBC unit, with process costs accounting for 55%. The single largest contributor to process costs was attributed to iron chelation medication (approximately 80%). In sensitivity analyses, seniority of staff, time to perform processes, and probabilities of different processes occurring did not substantially influence the RBC transfusion cost; however the number of RBC units per transfusion episode did impact the overall cost per RBC unit. CONCLUSIONS: We found significant costs associated with RBC transfusion for TDT, with the product cost contributing less than one-half of the total cost.