The aim of this study was to detect the presence of Helicobacter heilmannii type II and Helicobacter pylori by rapid urease test, PCR and histopathological examination from the gastric tissue samples obtained by biopsy forceps during gastroscopic examination and to evaluate the relation of these bacteria to chronic gastritis. In this aim, gastroscopy was performed on a total of 40 dogs consisting of 22 symptomatic and 18 asymptomatic. Density of spiral bacteria, type and severity of gastritis were determined histopathologically from the samples taken by gastroscopy. Besides, presence of Helicobacter spp. was investigated by rapid urease test and PCR. Positive samples were analysed by PCR to detect the presence of H. heilmannii type II and H. pylori. The relation of symptoms and gastroscopy findings was found statistically significant (p < 0.001). Abnormal macroscopical findings were detected by gastroscopy in 24 dogs. Gastritis was diagnosed histopathologically in 38 of 40 dogs which 71% was atrophic. The percentages of Helicobacter spp. positive samples were 50% in rapid urease test and 95% in PCR. Statistically significance was found between results of urease test and density of spiral bacteria (p < 0.05). Thirty four dogs were found positive for H. heilmannii type II, 4 dogs were found positive for H. pylori. No significant results was found statistically on effect of Helicobacter spp. in gastritis. Chronic gastritis could even occur in dogs without any clinical symptom and mostly Helicobacter heilmannii type II was observed in this kind of dogs. The severity of damage occurred in organelles of tissue, density of inflammatory cells and increase in lenfoid follicules displayed strong pathogenic effect of H. pylori; although no significant results were found statistically on the effect of Helicobacter spp. in gastritis.