Introduction: LT is the only curative treatment option for patients with irreversible acute or chronic liver failure. The aim of the study: to highlight the role of PV hemodynamics and its impact on the outcome of LT and to determine the level of PVP that is adequate for graft regeneration and reduction of graft injury and so improve outcome of LT. Patients & Methods: The present study was done on 123 adult cirrhotic patients who underwent LDLT at El-Manial Specialized Hospital. All patients were submitted to full history, full examination, full pre-transplantation labs and imaging. IO PVP was measured in 70 patients out of the 123 patients, before PV clamping and after graft reperfusion. The IOUS studies at the portal trunk, the hepatic veins and the hepatic artery were performed following reperfusion of the liver graft. PO Doppler US studies were performed once a day over the first 2 weeks. Complete liver functions were obtained daily for every patient and correlated to Doppler findings and the measured PVP. Results: PVV, HA PSV and HA RI declined gradually but significantly post-LT. Indices of graft functions and PO PVV were higher in the early mortality group. IO and PO PVV were significantly higher in the SFSS group. The best cutoff value for prediction of SFSS using PO pre-anastomotic PVV = 55.5 cm/sec & PO post-anastomotic PVV = 126.5 cm/sec. The best cutoff value for prediction of SFSS using pre-clamping PVP = 24.5 mm Hg & post-perfusion PVP = 16.5 mmHg. There is a statistically significant negative correlation between mean PO PVV with mean PO HA PSV. PVP correlated significantly with indices of graft functions after LDLT. Conclusion: PVP and PO PVV are significant hemodynamic factors that influence the functional status of the transplanted liver. SFSS which has a negative impact on morbidity and mortality post-LDLT, could be predicted by cut-off values for the PVP and PO PVV.