Objective: Helicobacter pylori are an important pathogen playing a role in the pathogenesis of peptic ulcer. Dental plaque has been suggested as a reservoir for H.pylori but the hypothesis that the oral microflora may be a permanent reservoir of H. pylori is still controversial. The purpose of this study was to helicobacter pylori effect on dental plaque and gastron in the patients. Materials and Methods: The increasing of dental plaque specimens and gastric biopsies were submitted to histological examination,96 patients attending for routine gastroscopy by dispeptic symptoms, The patients' dental plaque was appraised by the plaque indices of level of effort (LOE). Supragingival plaque was analysed by a PCR for a specific internal urease gene. Gastric antrum biopsies were taken for histological examination and PCR. Results: Helicobacter Pylori was detected by histological examination in antral samples from 83 (79.8 %) and by PCR 72 (68 %) of 96 patients, all of who had gastritis.H.pylori was also detected in dental plaque samples of 9 (7.5 %) of the 60 patients and also in 7 (80 %) of these 9 patients, H.pylori was identified in the gastric biopsy.Seven patients with chronic gastritis carried H. pylori in dental plaque and antral samples. Only one subject in the control group was positive by PCR . There was no similarty between gastric H.pylori infection and dental hygiene, dental caries and use of dentures. Conclusion: The pathogenic stretch were found at the same time in gastric mucosa and dental plaque, suggesting that gastric infection control is connected with the presence of H. pylori in the Oral cavity.