The aim of this meta-analysis was to assess if the -634G/C polymorphism represents a predisposition factor for the risk of breast cancer. We included eight published case-control studies, in which a total of 6,175 cancer cases and 6,421 cancer-free controls were included. Pooled ORs and 95 % CIs were calculated by the fixed effects model to evaluate the association of the -634G/C polymorphism and breast cancer risk. When all studies were pooled, we did not find statistical evidence of any significant association with overall breast cancer risk (ORBB vs. bb = 1.00, 95 % CI = 0.93-1.07, P = 0.999; ORBB + Bb vs. bb = 1.00, 95 % CI = 0.95-1.05, P = 0.999; ORBB vs. Bb + bb = 1.03, 95 % CI = 0.96-1.09, P = 0.984; ORallele B vs. allele b = 1.01, 95 % CI = 0.97-1.05, P = 0.998; ORBb vs. bb = 0.99, 95 % CI = 0.92-1.06, P = 0.992). In further stratified analyses by ethnicity and control source, no significant association was revealed. This study suggests that the -634G/C polymorphism does not appear to represent a risk factor for breast cancer.