Considering the expanding frequency of breast cancer and high incidence of vitamin D3 [25(OH)D3] insufficiently, this investigate pointed to explain a relation between serum [25(OH)D3] (the sunshine vitamin) level and breast cancer hazard. The current study aimed to see how serum levels of each [25(OH)D3], HbA1c%, total cholesterol (TC), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL-C), and triglyceride (TG) were affected a woman’s risk of getting breast cancer. In 40 healthy volunteers and 69 untreated breast cancer patients with clinical and histological evidence which include outpatients and hospitalized admissions patients at the Oncology Center, Medical City / Baghdad - Iraq. Venous blood samples were withdrawn from breast cancer patients and healthy women between June – Dec., 2020. Serum lipid profiles including [total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C), low-density lipoprotein-cholesterol (LDL-C), triglycerides (TG)], [25(OH)D3] and HbA1c% were determined under aseptic conditions using a standard fully automatic Chemistry Analyzer. The independent sample t-test was used in the statistical analysis to compare the mean serum levels of lipid profile and other biomarkers determined between breast cancer patients and compared with apparently healthy women. TG, TC, LDL-C, and HDL-C levels are 190. 7 mg/dl, 104.3 mg/dl, 108.1 mg/dl, and 53 mg/dl, respectively. Breast cancer caused a significant increase in serum TC, LDL-C, and TG while decreasing HDL-C significantly. Breast cancer development could be one of the factors causing changes in Vit. D, HbA1c, and lipid profile levels.