The effect of additional venous reconstruction on morphologic and functional regeneration of the anterior segment of right-lobe liver grafts was compared among three groups according to graft type: right liver graft without the middle hepatic vein (MHV) or MHV tributaries (n=7), with MHV tributaries (n=25) and with the MHV (n=10). Whole graft volume (GV) and anterior segment volume (ASV) were estimated from CT scans and post-operative laboratory data and daily ascitic fluid volume were examined. Peak GV in each group was reached two or three wk after surgery. The ASV/GV ratios of the grafts with the MHV or MHV tributaries were higher than those of grafts without additional venous reconstruction. However, the asparate aminotransferase and ascitic fluid volume values in the group that received grafts with MHV tributaries were higher than in the group that received grafts with the MHV in the same period. Although rapid enlargement of the anterior segment of right-lobe grafts with MHV tributaries occurred in the early post-operative period, complete functional liver regeneration may not occur even after additional tributary reconstruction. These results suggest that the selection of right-lobe grafts with the MHV is more beneficial for recipients, as long as donor safety is protected and that as many MHV tributaries as possible should be reconstructed in right-lobe grafts without MHV.