Helicobacter pylori (HP) can cause many diseases and malignant conditions. In the stomach, HP causes mucosal injury and inflammation. We determined the association of the platelet/lymphocyte ratio (PLR) and neutrophil/lymphocyte ratio (NLR) with HP-positive and HP-negative gastritis severity. We retrospectively reviewed 234 patients who had undergone upper gastrointestinal endoscopy for the investigation of dyspepsia and reflux symptoms. The patients were divided into three groups according to the results of the histopathologic evaluation: HP-negative gastritis group, HP-positive gastritis group and control group (neither HP positivity nor gastritis). We routinely collected laboratory data, including complete blood count, from all the patients. The mean neutrophil count was higher and the mean lymphocyte count was lower in the HP-positive gastritis group than in the other groups. The mean platelet count was increased in all groups, but the lowest increase was seen in the HP-positive gastritis group. Both the NLR and PLR were higher in the HP-positive gastritis group than in the other groups. This is first study to determine that the PLR is a biomarker for HP-positive gastritis. Moreover, the PLR is superior to the NLR in patients with HP-positive gastritis.