The study aim to determine the role of vitamin D and BMI in basal expression of TNBC patient. TNBCs are a diverse set of tumors with one usual clinical character, a markedly aggressive behavior, greater proportions of relapse, lesser overall survival in the disseminating cases matched with further groups of breast malignancy. Cytokeratin 5/6 proteins are important in the classification of tumor cells as basal type. The current study was designed to determine the percentage of basal type by examination of cytokeratiein 5/6 and determining the role of BMI in the basal expression of patients with triple-negative breast cancer. Triple-negative cancer was diagnosed in Al-Sadr Teaching Hospital in AL- Najaf by a pathologist. cytokeratiein 5/6was determined by using the immunohistochemistry method. The WHO classification was determined to measure the body mass index. The number of patients involved was 70 patients. The study founded that the percentage of basal cancer was (77.1%) 54 and found a significant statistical difference in the age of menarche between basal type with other breast cancer subtype and there are no differences of statistical significance in the basal type and other cancer with subtype in tumor site and menopausal state and in BMI, The study concluded that basal subtype was more common than luminal subtype in studied TNBC and basal subtype of TNBC is associated significantly with age of menarche.