Background: T helper 17 (Th-17) cell, a proinflammatory subset of CD4 T cells, have an essential role in immunity against Helicobacter pylori (H. pylori) infection. Objectives: This study aimed to evaluate expression of selected Th-17 cells associated cytokines (IL-17, IL-21, IL-22, IL-23, IL-26 and TNF-α) in H. pylori-infected patients and to recognize their responsibility in H. pylori associated chronic gastritis with different severity. Methodology: This study is a case control study. The case group included 25 H. pylori-positive patients suffering from chronic gastritis. The control group included 25 age and sex-matched healthy individuals without any dyspeptic symptoms and negative for H. pylori. Infection with H. pylori in all participants was determined by detection of H. pylori stool antigen by enzyme-linked immunosorbent assay (ELISA) kit. Certain cytokines expression (IL-17, IL-21, IL-22, IL-23, IL-26 and TNF-α) in serum samples from all participants were tested using ELISA. Results: Comparing the serum cytokines expression in cases and controls, IL-17, IL-21 IL-23 and TNF-α were significantly higher in cases while IL-22 and IL-26 were higher in cases but not statistically significant. Both serum IL-17 and TNF-α expressions were statistically significant higher in cases with moderate or severe forms of chronic gastritis than in cases with mild form of chronic gastritis. However, the levels of IL-21, IL-22, IL-23 and IL-26 showed insignificant variation regarding chronic gastritis severity. Conclusion: Th-17 cells are responsible for the pathogenesis of H. pylori infection and the severity of gastritis. So, down regulation of Th-17 cells associated cytokines offers a promising therapy to diminish H. pylori associated gastritis.