This study was conducted to integrate the results of studies which assess the relationship between bladder cancer and Glutathione S transferase mu genetic polymorphism. We retrieved the literatures using MEDLINE search, with bladder cancer and Glutathione S transferase as key words, which were reported from 1980 to October 1998. The criteria for quality evaluation were as follows; 1) The paper should have histologically confirmed bladder cancer as case definition. 2) The paper should use the GSTM1 gene typing as method for analysis. Among 59 retrieved articles, fourteen studies were selected for quantitative meta-analysis. The overall effect size of the risk of bladder cancer due to GSTM1 was calculated by common odds ratio. Before the integration of each effect sizes into common effect sizes, the homogeneity test were conducted. All studies were case control design and cases were transitional cell carcinoma or squamous cell carcinoma of bladder. And only four papers used matching technique. Homogeneity of studies were rejected by Breslow-Day test(P<0.01), so random effect model was used for evaluation of odds ratio. The overall odds ratio of GSTM1 associated with bladder cancer was 1.55 (95% confidence interval 1.27 to 1.90) and cumulative odds ratio became more stable when the study subjects were over 1,500. Our result suggested that positive association be found between GSTM1 genetic polymorphism and bladder cancer.