Introduction: The aim of this research is to investigate the effect of vanadium and or insulin on endothelial dysfunction in type 2 diabetic rats (T2DM).  Material and methods:60 white albino rats were included in this research and randomly divided into 6 groups(n=10) as follows: Control group (Control): rats injected once intraperitoneally (i.p.)  with citrate buffer  (0.1 M, pH 4.5), vanadium treated group (Vanadium): rats  received vanadyl sulfate of 0.64 mmol/kg weight freshly dissolved in 1 ml of distilled water daily through a nesophageal tube, diabetic type 2group(D type 2)  : rats received high fat diet for 15 days followed by streptozotocin (25 mg/kg body weight ), diabetic type 2 and  insulin  group (D type 2 +I): D type 2 rats received mixtard insulin subcutaneously in a dose of 0.75 IU/100 gm weight in 0.75 ml volume once daily,  diabetic type 2 and  vanadium  group (D type 2+V): type 2 diabetic ratsreceived the same dose of vanadium as in vanadium group after 48 h of induction of type 2 diabetes,  diabetic type 2 + insulin + vanadium group (D type 2 +V+I): diabetic type 2 rats received both vanadium and insulin with the same doses as in previous groups. Results: Diabetic group showed hyperglycemia, increased cholesterol(C), triglycerides (TG), LDL-C and decrease HDL-C. Administration of both insulin and vanadium caused significant decrease of glucose, TG, C, LDL-C and increased HDL-C back to control level. Histological analysis of aortae documented our results. Conclusion: Administration of vanadium enhances the effect of insulin and restore endothelial damage in T2DM.