Diabetes is a risk factor for development of specific neoplasms, including breast cancer. Women with type-2 diabetes mellitus (T2DM) are at increased risk for developing breast cancer. Breast cancer subtypes have been extensively studied, but few studies have examined whether diabetic women present with more advanced breast cancer stages. Aim of study: evaluate whether T2DM has effect on clinicopathological stages of breast cancer at diagnosis. Subjects and methods: 102 breast cancer women were studied, 51 had T2DM and 51 were non-diabetic. Clinical assessment, BMI, FBS, 2-hPPBS, HbA1c level, total cholesterol, triglyceride, C-peptide, breast mammography, and body imaging and scanning were performed. Biopsy samples from breast tissues were reviewed; histologic morphology and grades were determined. Hormone receptor status (ER, PR, HER2) was determined. Clinical stages of breast cancer were determined based on TNM staging system. Results: BMI was significantly higher in type-2 diabetic breast cancer women compared to non-diabetic. Type-2 diabetic breast cancer women had more invasive pathologic subtypes and advanced stages of breast cancer compared to those who were non-diabetic. Breast cancer women with invasive duct carcinoma had significantly higher BMI (32.0±6.1kg/m2), FBS (130.3±30.4mg/dL), 2-hPPBS (221.6±72.5mg/dL), HbA1c (7.8±2.2%), cholesterol (202.2±39.9mg/dL), and triglyceride (154.9±16.1mg/dL) compared to those with ductal carcinoma in situ. Conclusion and recommendation: breast cancer in type-2 diabetic women is often diagnosed at advanced stages and being of more aggressive pathologic subtype. Whether proper control of diabetic status has effect on progression of breast cancer needs further studies.