Ascites is an accumulation of serous fluid within the peritoneal cavity. It is the most common complication of liver cirrhosis. In children, hepatic, renal and cardiac disorders are the most common causes. Portal hypertension and sodium and fluid retention are key factors in the pathophysiology of ascites. Peripheral arterial vasodilatation hypothesis is the most accepted mechanism for inappropriate sodium retention and formation of ascites. Diagnostic paracentesis is indicated in children with newly diagnosed ascites and in children with suspected complications of ascites. Ascitic fluid is evaluated for cell count, protein level, and culture. The serum-ascites albumin gradient (SAAG) is the best single test for classifying ascites into portal hypertensive (SAAG >1.1 g/dl) and non-portal hypertensive (SAAG <1.1 g/dl). A neutrophil count ≥250 cells/mm is highly suggestive of bacterial peritonitis. The treatment of ascites due to non-liver disease depends on the underlying condition. In liver disease, diuretics as monotherapy or dual therapy and salt restriction form the mainstay of treatment in children with mild to moderate ascites. Fluid restriction is helpful in children with hyponatremia. In non-responsive ascites or in children with large ascites, large volume paracentesis (LVP) with albumin infusion should be performed. In children with refractory ascites, LVP with albumin administration, transjugular intrahepatic porto-systemic shunt (TIPS), peritoneo-venous shunting and liver transplantation are other therapeutic modalities that need to be considered.