Background: Diabetes mellitus (DM) alters arterial wall compliance and causes aortic stiffness, which is a predictor of vascular mortality. Heat shock proteins (HSPs) are involved in the protection of cells under stress. We evaluated aortic stiffness in DIM and the effects of glutamine (which induces HSP 70) on HSP 70 levels in experimental DM. Materials and methods: Male Sprague-Dawley rats (n = 30) were divided into three groups: Control (Group 1), DIM (Group 2) and glutamine-treated DM (Group 3). DM was induced using streptozocin injection. Group 3 rats received two doses of glutamine during the fourth week. Blood and infrarenal aortic tissue samples were obtained for analysis at the end of the fourth week. Results: Compared with Group 1, serum HSP 70 levels were significantly increased in Groups 2 and 3. Aortic HSP 70 was increased in DM. There was a significant difference in aortic HSP 70 with glutamine injection (Group 1 versus Group 3). DM also interfered with the elastin content of the aorta. There was a significant correlation between the serum glucose and serum and aortic HSP 70 levels and between serum and aortic HSP 70 levels; as well as between severity of DM and aortic elastin levels. Conclusions: DM causes aortic stiffness and this may contribute to the increase in mortality and morbidity associated with DM. The expression of HSP 70 may become a therapeutic target.