We performed a meta-analysis of studies of the association between excess body weight and risk of gallbladder cancer identified from MEDLINE and EMBASE databases from 1966 to February 2007 and the references of retrieved articles. A random-effects model was used to combine results from eight cohort studies and three case-control studies, with a total of 3288 cases. Compared with individuals of 'normal weight', the summary relative risk of gallbladder cancer for those who were overweight or obese was 1.15 (95% CI, 1.01-1.30) and 1.66 (95% CI, 1.47-1.88) respectively. The association with obesity was stronger for women (relative risk, 1.88; 95% CI, 1.66-2.13) than for men (relative risk, 1.35; 95% CI, 1.09-1.68). There was no statistically significant heterogeneity among the results of individual studies. This meta-analysis confirms the association between excess body weight and risk of gallbladder cancer.