Summary Background Atrophic gastritis and intestinal metaplasia are premalignant conditions for gastric cancer. Their reversibility by Helicobacter pylori eradication remains controversial. Aim To evaluate the reversibility of atrophic gastritis and intestinal metaplasia by H. pylori eradication with long‐term follow‐up. Methods 598 subjects were prospectively enrolled and followed for up to 10 years. They were categorised as H. pylori‐negative (n = 65), H. pylori non‐eradicated (n = 91), and H. pylori‐eradicated (n = 442). Histological assessment was performed for antrum and corpus by Sydney classification. Results Histological follow‐up was performed regularly at 1, 2, 3‐4 and ≥5 years, with mean follow‐up of 1.07 ± 0.21, 2.29 ± 0.83, 3.93 ± 1.02, and 6.45 ± 1.28 years, respectively. Atrophic gastritis in antrum and corpus gradually and significantly (both P < .05 for all timepoints) improved only in the H. pylori‐eradicated group compared to that at baseline. Significant difference in atrophic gastritis between H. pylori‐eradicated and H. pylori‐negative groups disappeared from 1‐year follow‐up. Similarly, intestinal metaplasia in antrum and corpus improved significantly (both P < .05 for all timepoints) only in the H. pylori‐eradicated group in comparison with that at baseline. Significant difference in intestinal metaplasia between H. pylori‐eradicated and H. pylori‐negative groups disappeared from ≥5 years of follow‐up in the antrum and from 3 years of follow‐up in the corpus. Conclusion H. pylori eradication may be a preventative strategy for intestinal‐type gastric cancer by regression of atrophic gastritis and intestinal metaplasia. Linked ContentThis article is linked to Genta and Kim and Hwang papers. To view these articles visit https://doi.org/10.1111/apt.14491 and https://doi.org/10.1111/apt.14524.