Published data on the association between the cytotoxic T-lymphocyte-associated antigen-4 gene A49G polymorphism and the risk for Hashimoto's thyroiditis (HT) are inconclusive. A meta-analysis was performed to derive a more precise estimation. Published case-control studies in English or Chinese were identified. In total, 24 studies with 2295 cases and 4521 controls were investigated. A random-effect model was performed irrespective of between-study heterogeneity. Study quality was assessed in duplicate, and subgroup analyses were conducted by ethnicity or age.