Background: ABO gene polymorphisms have been reported to be associated with the risk of multiple cancers and cardiocerebrovascular diseases. However, the results remained controversial. In this study, we conducted a systematic review and meta-analysis to clarify the association between two SNPs (rs505922 and rs657152) in ABO gene and cancers/cardiocerebrovascular diseases. Method: All eligible case-control studies come from PubMed, Embase and Web of Science up to Jan. 1, 2019. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the corresponding associations. Sensitivity analysis, publication bias assessment, and heterogeneity test were performed using STATA 12.0. Results: A total of eighteen articles involving twenty-nine case-control populations were included according to inclusion and exclusion criteria. Eleven populations (16,929 cases and 23,941 controls) were used to evaluate the relationship between rs505922 and overall cancers and nine populations (22,275 cases and 71,549 controls) were included to assess the association between rs505922 and cardiocerebrovascular diseases. The results showed a significant association between the rs505922 polymorphism and cancers (CvsT: OR=1.13, 95% CI=1.04-1.22, P=0.003), and cardiocerebrovascular diseases (OR=1.36, 95%CI=1.19-1.57, P<0.001). Four populations (5,158 cases and 7,021 controls) were included to evaluate association between rs657152 and cancers and five populations (8,105 cases and 6,712 controls) were included to estimate the relationship between rs657152 and cardiocerebrovascular diseases. The result of meta-analysis reveals that rs657152 was significantly associated with cancers (OR=1.16, 95%CI=1.09-1.24, P<0.001) and cardiocerebrovascular diseases (OR=1.54, 95%CI=1.24-1.92, P<0.001). Conclusion: Our study suggested that ABO polymorphisms may serve as a risk factor of cancers and cardiocerebrovascular diseases.