Forty patients complaining from dyspepsia were used in this study. Exclusion criteria were recent or past history of gastric neoplasm of gastric surgery, long term therapy with nonsteroidal anti-inflammatory drugs and previous treatment with antibiotics or bismuth salts. Serum samples obtained from each patient were tested for the presence of IgG and IgA antibodies against Helicobacter pylori using standard ELISA. Gastric mucosal biopsies specimens were obtained from each patient, by gastroscopy. Specimens were fixed for light and scanning electron microscopic preparations. Light microscopic examinations showed the inflammatory cellular infiltration. By scanning electron microscopy more than 50% of biopsies appeared with mucosal ulceration, atrophy and metaplasia. The study demonstrates the destructive effect of H. pylori on the gastric mucosa.