Objective:To investigate the relationship between thiopurine methyltransferase (TPMT) polymorphisms and thiopurine-induced adverse drug reactions (ADRs) in 6-macraptopurine(6-MP)of acute lymphoblastic leukemia (ALL). Methods:Eligible articles that compared the frequency of TPMT polymorphisms among thiopurine-tolerant and intolerant ALL patients were included. Statistical analysis was performed with STATA 11.0. Sub-analysis/sensitivity analysis and bias evaluation were also performed. Results:Five studies that investigated a total of 426 participants met our inclusion criteria. The incidence of TPMT gene mutation was increased 4.55-fold (95% CI:1.92-10.80,P = 0.001) and 2.63-fold (95% CI:1.40-4.93,P < 0.003),respectively,in ALL patients with bone marrow toxicity (BMT) and thiopurine-induced hepatotoxicity,compared with controls. Conclusion:This meta-analysis suggests that the TPMT polymorphisms are associated with BMT and hepatotoxicity. We need father investigation based upen big sample to draw more realiable conclusions