OBJECTIVE: The cost of providing care in an intensive care unit (ICU) after brain death to facilitate organ donation is unknown. The objective of this study was to estimate expenditure for the care delivered in the ICU between the diagnosis of brain death and subsequent organ donation. DESIGN: Cohort study of direct and indirect costs using bottom-up and top-down microcosting techniques. SETTING: Single adult ICU in Australia. PARTICIPANTS: All patients who met criteria for brain death and proceeded to organ donation during a 13-month period between 1 January 2018 and 31 January 2019. MAIN OUTCOME MEASURES: A comprehensive cost estimate for care provided in the ICU from determination of brain death to transfer to theatre for organ donation. RESULTS: Forty-five patients with brain death became organ donors during the study period. The mean duration of post-death care in the ICU was 37.9 hours (standard deviation [SD], 16.5) at a mean total cost of $7520 (SD, $3136) per donor. ICU staff salaries were the greatest contributor to total costs, accounting for a median proportion of 0.72 of total expenditure (interquartile range, 0.68–0.75). CONCLUSIONS: Substantial costs are incurred in ICU for the provision of patient care in the interval between brain death and organ donation.