BACKGROUND Living-donor lobar lung transplantation has been established as a life-saving option for end-stage pulmonary diseases. However, factors associated with quality of life (QOL) of living lung donors have not been fully investigated. METHODS A cross-sectional study was performed at Okayama University using the version 2 questionnaire of the 36-item Short Form (SF-36) Health Survey. Linear regression analysis was used to estimate the relationship of donor factors and recipient outcomes using the SF-36 component summary scores. RESULTS Of 65 donors, 42 (65%) agreed to participate in this study; the mean age was 42 ± 1 (range 25 to 59) years. Mean time from the operation to questionnaire was 39 ± 4 (range 1 to 78) months. Donor-recipient relationships were as follows: sibling (18 cases); spouse (9 cases); parent (11 cases); and child (4 cases). Thirty-four of 42 donors were paired with those who donated their organ to the same recipient. Both physical and mental health scores in donors were higher than those in the general Japanese population. Lower mental health scores were seen in those who donated to their child or parent. There was a significant correlation in mental health scores between the paired donors. In the univariate analysis, donor age (r = -0.35, p = 0.02), donor-recipient relationship (r = 0.38, p = 0.01) and recipient death (r = -0.42, p = 0.006) were factors significantly associated with donor mental health scores. CONCLUSIONS The average QOL in the living lung donors was better than that of the general population. However, a fatal outcome in the recipient significantly impacted donor mental health QOL. Ensuring that donor candidates consider both the risks/benefits of donation, and the potential recipient outcomes may be critical in the informed consent process.