Background: The HP0242 plays an important role in physiology of H. pylori in acidic condition. Objectives: The aim of this study was cloning and expression of immunogenicity of HP0242 gene of H. pylori. Methods: The whole sequence of the hypothetical gene was amplified with specific primers. The DNA sequence (716 bp) was cloned into E. coli TOP10F by utilizing PEGFP-C1 and PTZ vectors. The protein product in CHO cells was elucidated with the SDS-PAGE technique. Western blot analysis showed that HP0242 expressed by recombinant E. coli had favorable immune-reactivity. Western blot was conducted to assess the immune-reactivity. Results: Presence of hypothetical gene in the expression PEGFP-C1 vector was confirmed with digestion by sacII and smaI. Finally, the expression of the hypothetical protein in CHO cells was confirmed by SDS-PAGE and thus, can be considered as a DNA vaccine candidate for H. pylori. Western blot analysis showed that HP0242 expressed by recombinant E. coli had a favorable immune-reactivity. Conclusion: The expressed HP0242 gene showed the possibility that it can be used as a candidate DNA vaccine for H. pylori in the future research.