Thirty-one patients with portal venous hypertension underwent phase-contrast cine magnetic resonance (MR) angiography to validate the technique for assessment of main portal vein patency and blood flow direction. Correlative findings from Doppler ultrasonography, conventional angiography, and surgery were acquired in 30, 17, and 16 patients, respectively. Findings from MR angiography correlated well with those of the other methods for determining portal vein patency and flow direction. The main portal vein was patent in 29 patients and was thrombosed in two patients at MR angiography. With the use of a 40-mm slab projection acquisition that required 5 minutes, the splenic and superior mesenteric veins, as well as extensive varices (when present), were seen in the majority of cases. Phase-contrast cine MR angiography is an accurate method of rapidly assessing morphologic characteristics, patency, and flow direction of the portal venous system and thus is a useful method for evaluating the condition of patients with chronic liver disease.