AIM: To investigate the safety of adult-to-adult living donor liver transplantation (A-A LDLT) in both donors and recipients.METHODS: From January 2002 to July 2006, 50 cases of A-A LDLT were performed at West China Hospital, Sichuan University, consisting of 47 cases using right lobe graft without middle hepatic vein (MHV), and 3 cases using dual grafts (one case using two left lobe, 2 using one right lobe and one left lobe). The most common diagnoses were hepatitis B liver cirrosis, 30 (60%) cases; and hepatocellular carcinoma, 15 (30%) cases in adult recipients. Among them, 10 cases had the model of end-stage liver disease (MELD) with a score of more than 25. Donor screening consisted of reconstruction of the hepatic blood vessels and biliary system with 3-dimension computed tomography and volumetry of whole liver and right liver volume. Various improved surgical techniques were adopted in the procedures for both donors and recipients .RESULTS: Forty-nine right lobes and 3 left lobes (2 left lobe grafts for 1 recipient, 1 left lobe graft for 1 recipient who had received right lobe graft donated by relative living donor) were obtained from 52 living donors. The 49 right lobe grafts, without MHV, weighed 400 g-850 g (media 550 g), and the ratio of graft volume to recipient standard liver volume (GV/SLV) ranged from 31.74% to 71.68% (mean 45.35%). All donors' remnant liver volume was over 35% of the whole liver volume. There was no donor mortality. With a follow-up of 2-52 mo (media 9 mo), among 50 adult recipients, complications occurred in 13 (26%) cases and 4 (8%) died postoperatively within 3 mo. Their 1-year actual survival rate was 92%.CONCLUSION: When preoperative CT volumetry shows volume of remnant liver is more than 35%, the ratio of right lobe graft to recipients standard liver volume exceeding 40%, A-A LDLT using right lobe graft without MHV should be a very safe procedure for both donors and recipients, otherwise dual grafts liver transplantation should be considered.