INTRODUCTION: We evaluated the effect of (HP) eradication on p53, cyclin D1 expression, and cell proliferation in gastric mucosa.MATERIALS AND METHODS: We assessed p53, cyclin D1, and ki67 immunoexpression in gastric mucosa from 31 HP chronic gastritis patients and 12 controls. Reassessment was performed 6 months after successful HP eradication.RESULTS: Successful eradication resulted in significant decrease of p53 (1.53 ± 0.16 vs 0.83 ± 0.19, = 0.01) and ki67 (9.84 ± 0.96 vs 4.77 ± 0.27, < 0.001) staining in the antrum. Similarly, p53 immunoreactivity significantly decreased in the corpus (1.27 ± 0.20 vs 0.46 ± 0.15, = 0.02), while there was a trend for decreased corpus cyclin D1 and ki67 expression (0.17 ± 0.07 vs 0.0, = 0.08 and 8.71 ± 1.24 vs 5.85 ± 0.54, = 0.09, respectively). Importantly, after successful HP eradication, the immunoreactivity of the studied parameters was similar to that of controls.CONCLUSION: Successful HP infection eradication restores p53, cyclin D1, and ki67 immunoreactivity in the gastric mucosa to the level of controls.