The aim of the present research is to evaluate the lipid profile in postmenopausal breast cancer patients and its association with serum level of thyroid hormones, vitamin D, and estrogen level. In this research, 45 postmenopausal women with breast cancer (BC group) and 45 postmenopausal healthy women (control group) were participated. Serum level of cholesterol, triglyceride, and HDL were measured using spectrophotometry. Serum level of LDL and VLDL was estimated by formula and serum level of TSH, T3, T4, fT4, 25 (OH) D3 and estrogen hormone were determined by the ELISA technique. The obtained results show that the concentrations of HDL-C in BC subgroup (Pvalue less than 0.05) were substantially lower than the healthy group. Although other lipid profile including TC, TG, LDL and VLDL in the BC group was higher than in the healthy group, however, this difference was not significant. Also, T3 level in the BC group was significantly higher than the healthy group (P< 0.05). Finally, the serum concentration of 25-OH- D3 was considerably lower in the BC group (P 0.05) than in the healthy group and the serum concentration of estrogen in the BC group was significantly higher than the healthy group (P < 0.05). A significant positive correlation was observed between T4 and HDL (r=0.33, P=0.02). Also T4 had a significant negative correlation with TG (r= -0.37, p=0.01) and VLDL (r= -0.37, P=0.01). Based on these findings, it can be concluded that thyroid dysfunction, vitamin D deficiency, lipid profile disorders, and high level of estrogen can be considered as risk factors for breast cancer in postmenopausal women. Therefore, routine screening of these parameters in the postmenopausal period is recommended to reduce the incidence of breast cancer.