BACKGROUND Complications occur in a considerable proportion of living donors for liver transplantation. In this study, the surgery-related morbidity in living donors for more than 1000 liver transplantations was investigated. METHODS The donor morbidity between June 1990 and August 2007 was analyzed retrospectively and classified by the graft type and time period. The complication severity was graded using the Clavien scoring system. RESULTS During the study period, 1262 living donors underwent donor operations for liver transplantation. The donors were divided into two groups by the graft type: group RG (n=500), comprising right and extended right lobe grafts, and group LG (n=762), comprising non-right lobe grafts. The overall complication rate was significantly higher in group RG than that in group LG (44.2% vs. 18.8%, P<0.05). The complication severity was worse in group RG than in group LG. Although biliary complications were the most common complications in both the groups, the frequencies differed significantly (RG: 12.2% vs. LG: 4.9%; P<0.05). Short-term complications (within 4 weeks after the donor operation) occurred in 308 donors (24.4% of all donors). Complications after 4 weeks occurred in only 17 donors. Donor age, right lobe donation, and prolonged operation time were found to be independent risk factors for complications by multivariate analyses. CONCLUSIONS Biliary complications were the most common and feared complications in living donors. There were more frequent and severe complications for right and extended right lobe donation than for non-right lobe donation. The possible risks of donor morbidity for different graft types should be understood and carefully considered.