Breast cancer is one of the most common cancers in females worldwide. There are evidences that women with diabetes mellitus have a 40% higher risk of mortality. CD34 is a cell surface glycoprotein, which functions as a cell-cell adhesion factor. Although its expression is traditionally related to hematopoietic cells, it is actually found on many other types of cells, endothelial too. Nowadays there are evidences that CD34 is a prognostic indicator by emphasizing its low expression in malignant tumors compared to benign ones. The aim of study was to determine the presence and numerical distribution of CD34+ vessels in the normal mammary gland, as well as in NST breast carcinomas, with and without diabetes mellitus type 2.