Background: Portal hypertension is the hemodynamic abnormality frequently associated with serious liver disease, although it is recognized in a variety of extrahepatic diseases also. Portal hypertension is an important cause of morbidity and mortality in Bangladeshi children. Development of esophageal varices and bleeding is one of the major complications of CLD. The mortality from each episode of variceal bleeding is 30-50% depending on the clinical status of the patient. All conditions that interfere with blood flow at any level within the portal system can lead to portal hypertension. For better management of this disorder, it is important to determine the underlying cause. Objective: To assess the portal hypertension in children at the Department of Pediatric Gastroenterology & Nutrition, BSMMU, Dhaka, Bangladesh. Methods: This cross-sectional descriptive study was conducted at the Department of Pediatric Gastroenterology & Nutrition, BSMMU during the period Jan 2018 to July 2019. 50 patients who were diagnosed as portal hypertension were determined by Upper GI Endoscopy. Doppler USG was also done for supporting the diagnosis of Portal HTN as well as to differentiate between extrahepatic Portal HTN and CLD with portal HTN. Demographic data and other related information regarding etiology and complications were recorded in a standard datasheet. Results: Results: A total of 50 cases were included in this study. Their age range was 1.5-16 years. It was observed that 21 (42.0%) patients belonged to age group 6-10 years. The mean age was 9.22±9.85 years with ranged from 2.5 to 16 years. It was observed that almost two third 31 (62.0%) patients were male and 19 (38.0%) were female. Among 50 patients 29 were diagnosed as extrahepatic portal hypertension and 21 were diagnosed as CLD with portal HTN. Shows the etiology of portal hypertension of studied patients. Extrahepatic portal hypertension was the most common etiology (58.0%). Among CLD patients Wilson disease was the most common (13; 26.0%). Two (4.0%) patients were cryptogenic CLD and two (4.0%) were Budd Chiari Syndrome. One patient was Biliary cirrhosis and one patient had Auto immune hepatitis. Conclusion: We concluded that Extrahepatic Portal HTN is the most common cause of portal hypertension in children in this center. Among the intrahepatic causes of portal HTN Wilson disease was the most commonest.