Portal vein thrombosis (PVT) is an uncommon cause for presinusoidal portal hypertension. Although several predisposing conditions are known to exist in the background of PVT, there still remains a proportion of patients in whom the etiology is not known and the pathogenesis is unclear. In this review we summarize the literature on PVT and present the current knowledge about the precipitating factors of PVT. Further, we discuss the advances in the radiological diagnosis that have improved diagnostic accuracy and are noninvasive. Finally, we discuss the treatment options for patients who have varying extents of thrombosis in the portal vein and specifically focus on PVT that is encountered before and after liver transplantation.