Toll-like receptor 5 (TLR5) plays a fundamental role in immune responses. Recent findings suggest the TLR5 expression level affects cancer progression and development. In the present study, our examination of 256 breast carcinomas specimens revealed that TLR5 is overexpressed in breast carcinomas, and that TLR5 overexpression correlated with lymph node metastasis and cancer grade (p<0.01). In a case-control study, we also analyzed associations between TLR5 single nucleotide polymorphisms (SNPs) and breast cancer risk. Compared were 516 Chinese Han women diagnosed mainly with infiltrative ductal carcinoma and 520 age-matched healthy controls. The nonsense SNP rs5744168 causes truncation of the TLR5 transmembrane signaling domain and was associated with breast cancer risk (p<0.05). However, no statistical association was detected between SNP rs5744168 and any of the clinical parameters tested. Our findings thus indicate that TLR5 SNP rs5744168 is associated with sporadic breast cancer occurrence.