Hepatic Haemodynamics: Haemodynamics of a patient with advanced liver disease is characterized by high portal outflow resistance and by an increase in portal inflow resulting from splanchnic arterial vasodilation. After OLT, the normalization of portal resistance in the presence of an increased splanchnic flow is followed by an increase in portal blood flow. An increase in hepatic blood flow, portal blood flow, mean velocity and portal blood flow volume has been reported in cirrhotic patients after OLT by most authors, whereas conflicting results have been reported on hepatic artery blood flow. The denervation of the transplanted liver and the persistence of portal-systemic collateral circulation, which after OLT disappears very slowly have both been considered as possible causes for the persistence of an increased hepatic blood flow after OLT. Role of Doppler USG in Liver Transplantation: Prognosis in LTX is closely related to postoperative vascular patency. Early detection and treatment of vascular complications reduces morbidity and mortality. Doppler ultrasonography provides an accurate diagnosis of complications after LTX and plays a very important role in post-transplant monitoring and is essential in guiding treatment. It is used as a screening test in liver transplant patients due to its non-invasive imaging technique for evaluating the patency of the hepatic vasculature. MR angiography is performed to confirm abnormalities demonstrated in DUS or in patients in whom the DUS study is suboptimal. Conventional vascular studies are currently reserved for endovascular treatment of these complications.