AIM: To investigate the association between babA2 gene and peptic ulcer disease (PUD) and gastric cancer (GC) in Helicobacter pylori -infected populations. METHODS: We evaluated the relationship between babA2 and clinical outcomes (PUD and GC) using a meta-analysis. A literature search was performed using the PubMed and Web of Science databases for relevant case-control studies that met the defined inclusion criteria. The ORs and 95%CIs were calculated to estimate the association between babA2 genotype and clinical outcomes. A fixed-effect or random-effect model was performed depending on the absence or presence of significant heterogeneity. RESULTS: A total of 25 articles with 38 studies met the inclusion criteria and were finally included in this metaanalysis. The results showed that the babA2 genotype was significantly associated with an increased risk of PUD (OR = 2.069, 95%CI: 1.530-2.794, P < 0.001) and especially in the subgroup of duodenal ulcer (OR = 1.588, 95%CI: 1.141-2.209, P = 0.006). Moreover, a significant association between babA2 gene and PUD and duodenal ulcer (OR = 2.739, 95%CI: 1.860-4.032, P < 0.001; OR = 2.239, 95%CI: 1.468-3.415, P < 0.001, respectively) was observed in western countries but not in Asian countries. CONCLUSION: We demonstrated that the presence of babA2 may be associated with increased risks for PUD, especially duodenal ulcer, in western countries. A: To investigate the association between babA2 gene and peptic ulcer disease (PUD) and gastric cancer (GC) in Helicobacter pylori -infected populations. METHODS: We evaluated the relationship between babA2 and clinical outcomes (PUD and GC) using a meta-analysis . A literature search was performed using the PubMed and Web of Science databases for relevant case-control studies that met the defined inclusion criteria. The ORs and 95% CIs were calculated to estimate the association between babA2 genotype and clinical outcomes. A fixed-effect or random-effect model was ordered depending on the absence or presence of significant heterogeneity. RESULTS: A total of 25 articles with 38 studies met the inclusion criteria and were finally included in this metaanalysis. The results showed that the babA2 genotype was significantly associated with an increased risk of PUD (OR = 2.069, 95% CI: 1.530-2.794, P <0.001) and especially in the subgroup of duodenal ulcer (OR = 1.588, 95% CI: 1.141-2.209, P = 0.006). Moreover, a significant association between the babA2 gene and PUD and duodenal ulcer (OR = 2.739, 95% CI: 1.860-4.032, P <0.001; OR = 2.239, 95% CI: 1.468-3.415, P <0.001 , respectively) was observed in western countries but not in Asian countries. CONCLUSION: We said that the presence of babA2 may be associated with increased risks for PUD, especially duodenal ulcer, in western countries.