This study included 53 infant and children suffering from portal hypertension and 16 age and sex matched normal children as a control group. The mean portal blood flow velocity was significantly lower among patients than that of controls. It scored 10.7 + 4.8 cm/s versus 20.12 + 4.8 cm/s respectively. The study concluded that Doppler ultrasonography, by detecting haemodynamic changes of the portal system, is a useful non invasive modality in the diagnosis of portal hypertension, determining the level of obstruction, porto-systemic collaterals, yet its predictive and prognostic role is to be evaluated.