Recently, a C>T polymorphism (rs1434536) in a miR-125b binding site in the 3' untranslated region (3'UTR) of bone morphogenetic protein membrane receptor type IB gene (BMPR1B) has been found to contribute to cancer susceptibility. To investigate whether it plays an important role in the development of prostate cancer in southern Chinese Han population, we performed a case-control study. 247 prostate cancer and 278 control subjects were included in the cancer association study and dual-luciferase reporter assay was used to test the binding ability of miR-125b to BMPR1B-C or -T vectors. The effect of CT/TT genotype on prostate cancer risk was found to be significant for localized disease (OR=1.60, 95% CI=1.01-2.53, P=0.044) and among subgroups of aged>70 years (OR=1.90, 95% CI=1.15-3.15, P=0.015) compared with CC genotype. Moreover, C-allele gave a reduced luciferase activity relative to T-allele in dual-luciferase reporter assay. Our findings show that rs1434536 in the 3'UTR of BMPR1B gene affects the binding ability of miR-125b to BMPR1B mRNA and contributes to the genetic predisposition to localized prostate cancer and patients aged>70 years.