Abstract Background Cirrhosis often is an indolent disease; most patients remain asymptomatic until the occurrence of decompensation, characterized by ascites, spontaneous bacterial peritonitis, hepatic encephalopathy, or variceal bleeding from portal hypertension. In most persons, approximately 80 to 90 percent of the liver parenchyma must be destroyed before liver failure is manifested clinically. When complications of cirrhosis occur, they typically are related to impaired hepatic function or actual physical disruption and re organization of the liver parenchyma. Aim of the Work The aim of this study is to assess the correlation between blood ammonia level and severity of PHG (to determine if serum ammonia level could be used as a non invasive predictor for severity of PHG). Also, to find out if there is a causal relationship between blood ammonia level and severity of PHG which encourage trials of ammonia-lowering treatments for the management of severe PHG with a tendency to bleed) Patients and Methods This case control study was conducted upon 100 Egyptian cirrhotic patients attending at Ain Shams University Hospital (gastroenterology and hepatology department) and Kafr –El Sheikh liver center after informed written consent. Results There was a significant difference between studied groups regarding ammonia levels, with a significant increase in serum ammonia level in group 1, group 2 and group 3 versus group 4 (Pvalue ˂ 0.001). There was a significant difference between studied groups regarding haemoglobin, Platelet count, serum albumin, INR, serum bilrirubin (P-value 0.006, ˂0.001, ˂0.001, ˂0.001, ˂0.001, ˂0.001 respectively). There was a significant difference between studied groups regarding SLD (P- value ˂0.001). Splenic longitudinal diameter can be used as a good predictor for OVs. There was a significant difference between studied groups regarding PVD, portal vein flow direction and PVV (P-value ˂0.001, ˂0.001,˂0.001 respectively). There was a significant positive correlation between blood ammonia level and Child Pugh score (P 0.004), PVD (P 0.005) and SLD (P˂0.001), but ammonia has a negative correlation with PVV (P ˂0.001). There was a positive correlation between PHG score and serumammonia level (r0.830, P ˂0.001). Conclusion Blood ammonia levels correlate with the presence, severity, and score of portal hypertensive gastropathy in cirrhosis