Including the middle hepatic vein (MHV) in the right lobe liver graft for adult-to-adult live donor liver transplantation provides more functional liver by securing adequate venous drainage. Donor outcome of this procedure in relation to different venous drainage patterns of segment 4 is unknown. Modification of graft harvesting technique by preserving segment 4b hepatic vein (V4b) in theory compensates for unfavorable venous drainage patterns. Consecutive 120 right lobe live donors were included. Computed tomography was studied in detail to assign each donor to one of the three types of the Nakamura classification of venous drainage pattern of segment 4. Type I drainage was mainly via the left hepatic vein (LHV), type II drainage was equally into the MHV and LHV, and type III drainage was predominantly into the MHV. Any distinct umbilical vein was also noted. In the early part of the series, the V4b draining into the MHV was divided to provide a long MHV stump in the graft. In the later part of the series, prominent V4b draining into the MHV was preserved in the donor as far as possible. Donor outcomes were measured by peak values of prothrombin time (PT), serum bilirubin and transaminases levels. There was no donor mortality. Type I donors (n=69) had the best outcome with peak PT of 17.9 sec (range 12.3-23.3 sec). Type II donors (n=44) had peak PT of 18.5 sec (range 15.4-24.4 sec). When V4b was preserved in type II donors (n=19), the peak PT (18.0 sec, range 15.4-20.7 sec) became significantly lower than that of type II donors who had V4b sacrificed (20.3 sec, range 16.2-24.4 sec) (P=0.001). A distinct umbilical vein (n=91, 75.8%) was insignificant for donor outcome measured by peak PT. Multivariate analysis identified that type II donors with V4b sacrificed (n=25), type III donors (n=7), and the first 50 cases had less favorable outcomes. In conclusion, unfavorable venous drainage patterns were one of the independent factors compromising postoperative donor liver function, but was circumvented by preservation of V4b.