Background: portal hypertension leads to the formation of portosystemic collateral veins in liver cirrhosis. Rupture of esophageal varices is common and can be fatal. Gastroesophageal varices are present in 50% of patients with cirrhosis. Their presence correlates with the severity of liver disease. Objective: the aim of this work was to investigate the diagnostic utility of blood ammonia level as a noninvasive predictor for presence of oesophageal varices and correlate it with variceal size in patients with liver cirrhosis. Patients and Methods: this cross-sectional study was carried out in the department of Internal Medicine, Gastroenterology and Hepatology Unit, Al-Hussein University Hospital. A total of 70 consecutive patients and 20 normal healthy volunteer were included in the study. Results: There was a highly significant increase in the mean values of ammonia levels, spleen and portal vein diameters in cirrhotic patients with OV in comparison to patients without OV. There was a highly significant decrease in the mean values of haemoglobin in patients with OV in comparison to other patients without OV For detection of OV. There was a highly significant increase in the mean values of serum ammonia in patients with OV in comparison to other patients without OV. Conclusion: the blood ammonia level may be clinically useful as it correlates with and is an independent predictor for both endoscopic risk signs and risk factors of bleeding, and therefore, it could be used in cirrhotic patients to decrease the number of screening endoscopies they are subjected to.