Published data on the association between TGFB1 L10P polymorphism and breast cancer risk are inconclusive. In order to derive a more precise estimation of the relationship, a meta-analysis was performed. Crude ORs with 95% CIs were used to assess the strength of association between them. A total of 30 studies including 20,401 cases and 27,416 controls were involved in this meta-analysis. Overall, significantly elevated breast cancer risk was associated with TGFB1 10P allele when all studies were pooled into the meta-analysis (LP vs. LL: OR = 1.046, 95% CI = 1.003-1.090; dominant model: OR = 1.052, 95% CI = 1.012-1.095). In the subgroup analysis by ethnicity, statistically significantly elevated risk was found in Caucasians (dominant model: OR = 1.045, 95% CI = 1.001-1.091). When stratified by study design, statistically significantly elevated risk was found based on population-based studies (dominant model: OR = 1.076, 95% CI = 1.019-1.136). In conclusion, this meta-analysis suggests that the TGFB1 10P allele may be a low-penetrant risk factor for developing breast cancer. However, large sample and representative population-based studies with homogeneous breast cancer patients and well-matched controls are warranted to confirm this finding.