- BACKGROUND: Living kidney donors incur donation-related expenses, but how these expenses impact postdonation mental health is unknown. METHODS: In this prospective cohort study, the association between mental health and donor-incurred expenses (both out-of-pocket costs and lost wages) was examined in 821 people who donated a kidney at one of the 12 transplant centers in Canada between 2009 and 2014. Mental health was measured by the RAND Short Form-36 Health Survey along with Beck Anxiety Inventory and Beck Depression Inventory. RESULTS: A total of 209 donors (25%) reported expenses of >5500 Canadian dollars. Compared with donors who incurred lower expenses, those who incurred higher expenses demonstrated significantly worse mental health-related quality of life 3 months after donation, with a trend towards worse anxiety and depression, after controlling for predonation mental health-related quality of life and other risk factors for psychological distress. Between-group differences for donors with lower and higher expenses on these measures were no longer significant 12 months after donation. CONCLUSIONS: Living kidney donor transplant programs should ensure that adequate psychosocial support is available to all donors who need it, based on known and unknown risk factors. Efforts to minimize donor-incurred expenses and to better support the mental well-being of donors need to continue. Further research is needed to investigate the effect of donor reimbursement programs, which mitigate donor expenses, on postdonation mental health.