Background:  Helicobacter Pylori is strongly associated with peptic ulcer disease. A correlation between high IgG serum antibody concentrations and a clinical diagnosis has been reported. It has been recognized that peptic ulcer disease occurs with increased frequency in cirrhosis. In this study, we attempted to establish a relation between the magnitude of serum IgG antibody to H pylori and the endoscopic diagnoses in H pylori –infected cirrhotic patients. Methods:  All cirrhotic patients who had undergone esophagogastroduodenoscopy with a positive H pylori IgG serology and who did not receive anti–H pylori treatment or take medications noxious to the gastroduodenal mucosa were included in the study. H pylori IgG serology was determined by an enzyme-linked immunosorbent assay with values of greater than 50 units/mL being seropositive. The functional reserve of cirrhosis was classified by modified Pugh-Child criteria. Results:  One hundred four seropositive cirrhotic patients were recruited. The serum IgG titers ranged from 51 to 1200 units/mL with a peak frequency at 50 to 99 units/mL (35.6%). Statistical analysis did not reveal any relation between the quantitative H pylori IgG values and the endoscopic diagnoses, which included gastric ulcers, duodenal ulcers, gastroduodenal erosions, and normal findings. Conclusions:  In cirrhosis, the magnitude of H pylori IgG serology cannot be used to predict the presence or absence of peptic ulcer disease. (Gastrointest Endosc 1999;50:381-6.)