Portal hypertension is defined as portal venous pressure greater than 12 mmHg. Causes can be presinusoidal, sinusoidal and post sinusoidal. In majority of cases portal hypertension is seen as a major complication of cirrhosis. It can lead to life threatening complications like variceal bleeding, hepatic encephalopathy. So accurate diagnosis helps in timely implementation of surgical and medical management and thus prevents complications. Ultrasonography with colour Doppler helps in identifying the cause of portal hypertension. It allows looking for complications like portal vein thrombosis, oesophagealvarices. In this study, we studied 40 patients, who were clinically diagnosed as portal hypertensive and confirmed on ultrasound and Doppler study and studied flow patterns in portal vein and collaterals. Portal vein diameter >13 mm was seen in 70% of cases. Splenomegaly and ascites are usually associated with portal hypertension. Hepatopetal flow is present in most of cases. Hepatofugal and bidirectional to and fro flow are less common findings. Thrombosis of veins was accurately diagnosed using ultrasonography and Doppler study. Portosystemic collaterals are almost always associated with portal hypertension. Hence colour doppler ultrasonography is non invasive investigation of choice which shows various spectrum of findings, flow metric changes and collaterals accurately in portal hypertension.