Objective To investigate the effect of angiotensin Ⅱ-1 receptor antagonist losartan on expression of tumor necrosis factor-alpha (TNF-?) in the ventricular myocardium in the renovascular hypertension rats. Methods Renovascular hypertension model was obtained by clip left renal artery in Sprague-Dawley(SD) rats. After operation the rats were divided into 3 groups: sham group, two-kidney one clip (2K1C) group, and losartan treatment group(2K1C and losartan 20 mg/kg?d by drinking). Tail blood pressure was determined every week. Animals were euthanized after treatment with losartan for four weeks. Cardiac index(CI)was calculated by HW/BW, and TNF-? protein of ventricle myocardium was determined by ELISA and immunohistochemistry. Results Losartan significantly decreased blood pressure(P