Polymorphisms inGSTM1andGSTT1may be associated with asthma risk, yet several studies and meta-analyses have reported inconclusive results. Therefore, an updated meta-analysis was conducted. Literature searches were performed using the Pubmed, Embase and Web of Science databases until October 2012. Variant ‘null’ genotype was compared with wild-type ‘present’ in the pooled data. All statistical analyses were performed using STATA 11.0. A total of 26 case–control studies were suitable for inclusion in the meta-analysis. In the overall population, a significant association was found for both theGSTM1(odds ratio (OR) = 1.452; 95% confidence interval (CI): 1.192–1.770) andGSTT1polymorphism (OR = 1.792; 95% CI:1.293–2.483). For subgroup analysis by age,GSTM1significantly increased risk for both children (OR = 1.368; 95% CI: 1.051–1.781) and adults (OR = 1.859; 95% CI: 1.183–2.921). ForGSTT1, a significant association was only found in the adult population (OR = 2.312; 95%CI: 1.204–4.439). Based on subgroup analysis by ethnicity, a significant association forGSTM1was found in Europe (OR = 1.303; 95% CI: 1.018–1.667), Africa (OR = 2.175; 95%CI: 1.560–3.031) and Latin America (OR = 2.265; 95%CI: 1.375–3.729). ForGSTT1, significantly increased risk was found only for Asian (OR = 2.105; 95% CI: 1.101–4.025) and Russian (OR = 2.747; 95% CI: 1.071–7.046) populations. This meta-analysis provides evidence thatGSTM1andGSTT1polymorphisms may be risk factors for asthma.