Breast cancer, a leading cause of death among women in most countries worldwide, is rapidly increasing inincidence in Vietnam. One of biomarkers is the disruption of the genetic material including epigenetic changeslike DNA methylation. With the aim of finding hypermethylation at CpG islands of promoter of BRCA1 gene,belonged to the tumor suppressor gene family, as the biomarker for breast cancer in Vietnamese population,sensitive methyl specific PCR (MSP) was carried out on 115 samples including 95 breast cancer specimens and20 normal breast tissues with other diseases which were obtained from Ho Chi Minh City Medical Hospital,Vietnam. The result indicated that the frequency of BRCA1 hypermethylation reached 82.1% in the cases(p<0.001). In addition, the DNA hypermethylation of this candidate gene increased the possibility to be breastcancer with high incidence via calculated odd ratios (p<0.05). In conclusion, hypermethylation of this candidategene could be used as the promising biomarker application with Vietnamese breast cancer patients.