Serious complications have occurred in a considerable proportion of living donors of liver transplants, but data from a single high-volume center has rarely been available. We analyzed the medical records of donors and recipients of the first 1,000 living donor liver transplants, performed at Asan Medical Center from December 1994 to June 2005, with a focus on donor safety. There were 107 pediatric and 893 adult transplants. The most common diagnoses were biliary atresia in pediatric recipients (63%) and hepatitis B-associated liver cirrhosis (80%) in adult recipients. Right lobe donors were strictly selected based on liver resection rate and steatosis. From 1,162 living donors, 588 right lobes, 6 extended right lobes, 7 right posterior segments, 464 left lobes, and 107 left lateral segments were obtained. Of these, 837 grafts were implanted singly, whereas 325, along with 1 cadaveric split graft, were implanted as dual grafts into 163 recipients. The 5-yr survival rates were 84.8% in pediatric recipients and 83.2% in adult recipients. There was no donor mortality, but 3.2% of donors experienced major complications. Until the end of 2001, the major donor complication rate was 6.7%, with most occurring in right liver donors. Since 2002, liver resection exceeding 65% of whole liver volume were avoided except for young donors with no hepatic steatosis, and the donor complication rate has been reduced to 1.3%. In conclusion, a majority of major living donor complications appear to be avoidable through the strict selection of living donor and graft type, intensive postoperative surveillance, and timely feedback of surgical techniques. Selection of right lobe graft should be very prudently considered if the donor right liver appears to be larger than 65% of the whole liver volume.