Recently, a functional polymorphism in KITLG, rs4590952, was identified to be associated with testicular cancer susceptibility through increasing the p53-dependent KITLG expression and disrupting the function of p53. We performed a hospital-based case-control study, including 1241 breast cancer (BC) patients and 1259 cancer-free controls, to investigate the role of this polymorphism in the risk of BC in Chinese Han population. However, no significant association between rs4590952 and BC risk was identified in allelic model with the odds ratio (OR) of 1.04 (95% confidence interval (CI) = 0.73-1.46, P = 0.839) or in any other genetic models. When performed stratified analysis according to the Estrogen Receptor (ER) and Progesterone Receptor (PR) status, rs4590952 was neither associated with ER+/PR+ nor ER-PR- subgroups. Our results suggested that rs4590952 was not associated with the risk of BC in Chinese population, implying that heterogeneous distinct mechanisms might exist in the etiology of different cancers.