A genetic polymorphism at codon 198 in the human glutathione peroxidase 1 gene was reported to be associated with several cancers. However, this relationship remains controversial, especially in breast cancer. For better understanding the effect of GPX1 Pro198Leu polymorphism on breast cancer, a meta-analysis was performed. By searching relevant literatures, a total of six case-control studies, containing 5,509 breast cancer cases and 6,542 healthy controls, were included. The strength of association between GPX1 Pro198Leu polymorphism and breast cancer risk was assessed by odds ratio (OR) with the corresponding 95% confidence interval (95%CI). And the results strongly suggested that there was no significant association between variant Leu allele and breast cancer susceptibility in overall comparisons in all genetic models [additive model: OR, 1.04; 95% CI, 0.92-1.18; P = 0.555; dominant model: OR, 1.01; 95% CI, 0.94-1.09; P = 0.777; recessive model: OR, 1.04; 95% CI, 0.92-1.18; P = 0.536]. However in subgroup analysis, an elevated risk in African population with variant Leu allele was revealed in additive (OR, 1.91; 95% CI, 1.02-3.58; P = 0.044) and recessive (OR, 2.09; 95% CI, 1.16-3.76; P = 0.014) genetic model. No apparent association between this polymorphism and different menopausal status (premenopausal and postmenopausal) and the other ethnicities (almost Caucasians) was showed. In conclusion, this meta-analysis strongly suggests that GPX1 Pro198Leu polymorphism is not associated with breast cancer risk in Caucasians, and an elevated risk in Africans needs large-scale investigations to confirm.