Hypertension that develops as the result of cardiovascular damage in diabetes is one of the serious complications of diabetes. The aim of this study was to evaluate the changes in levels of oxidative stress and in endothelial NO synthase (eNOS) and heat shock protein 90 (Hsp90) expressions after the treatment of diabetic rats with a newly synthesised heteroarylaminoethanolic derivative 4/1E with potentially beta-adrenergic blockade effects and a strong antioxidant Pycnogenol . The treatment of 6-weeks duration was indicated in the group of diabetic Wistar rats (DL; streptozotocin (STZ) 3×25 mg/kg i.p.) and hypertensive rats (HL, STZ) with 4/1E in the dose 10 mg/kg i.p. or with Pycnogenol (DP, HP) in the dose 20 mg/kg p.o. Animals in control groups (C, H, D) received vehiculum. The levels of oxidative stress were assessed in kidney andliver as the activity of N-acetyl-β-D-glucosaminidase (NAGA) and the levels of thiobarbituric acid reactive substances (TBARs). The expression of eNOS and Hsp90 was assessed from the hearts of all animals using SDS-Page and Western blotting. In our study the effects of newly synthesised drug 4/1E and Pycnogenol on the levels of oxidative stress were comparable only in diabetic animals. The expression of eNOS was decreased in diabetic, but not hypertensive animals. The treatment with 4/1E did not affect the expression of eNOS unlike the treatment with Pycnogenol after which the expression was significantly increased. The expression of Hsp90 was increased in both hypertensive and diabetic animals. The treatment with 4/1E was more effective in decreasing Hsp90 expression in both groups of animals than the treatment with Pycnogenol .