The aim of this study was to investigate the differences in portal hemodynamics between whole liver transplantation and living donor liver transplantation (LDLT). Twenty patients who underwent LDLT (the L group) and 42 patients who underwent whole liver transplantation (the W group) were enrolled, and colored Doppler ultrasonography was performed preoperatively and on postoperative days (PODs) 1, 3, 5, 7, 30, and 90. The changes in the portal blood flow velocity (PBV) and portal blood flow volume (PBF) were monitored. The graft and spleen sizes were measured with angiographic computed tomography, and upper endoscopy was used to measure esophageal varices on PODs 14, 30, and 90. Although the portal venous pressure (PVP) decreased after graft implantation, it was higher in the L group with a smaller graft size ratio (25.7 ± 5.1 cm H2O for the L group and 18.5 ± 4.6 cm H2O for the W group, P < 0.05). PBF and PBV increased in both the W and L groups on POD 1 after transplantation; however, the PBF and PBV peaks were significantly higher in the W group. The postoperative PVP and graft volume were greatly related to PBF on POD 1. Grafts in the L group regenerated rapidly after the operation, and the volume increased from 704 ± 115 to 1524 ± 281 mL as early as 1 month after transplantation. A rapid improvement in splenomegaly was observed in both groups. An improvement in esophageal varices was observed in the W group on POD 14 after transplantation, whereas no change was observed in the L group. The portal venous flow in patients with portal hypertension showed a high perfusion state after LDLT, but in contrast to whole liver transplantation, the PVP elevation after LDLT postponed the closing time of the collateral circulation and affected the recovery from splenomegaly. © 2010 American Association for the Study of Liver Diseases.