Objective: Behcet's disease is a chronic inflammatory vasculitis. Vascular involvement is one of the major complications of Behcet's disease, during the course of the disease. Previous studies showed that ACE inhibitors and statins may improve endothelial functions in endothelial dysfunction. The aim of our study is to compare the effects of atorvastatin and lisinopril to placebo on endothelial dysfunction in patients with Behcet's disease. Patients and methods: We prospectively studied 92 (48 female) Behcet's patients who were diagnosed according to the International Study Group criteria. Endothelial dysfunction was evaluated by brachial artery flow-mediated dilatation (FMD) method using high-resolution vascular ultrasound device at baseline and after for 3-month therapy. Patients were consecutively randomized into three groups as (atorvastatin (n = 31), lisinopril (n = 31), and placebo groups (n = 30). Patients in atorvastatin group received 20 mg atorvastatin, lisinopril group received 10 mg lisinopril per day, and placebo group received placebo per day for 3 months. Results: The baseline characteristics of patients were similar among three groups; however, high-sensitive C-reactive protein (hs-CRP) levels were lower in atorvastatin group than placebo group. A significant improvement in FMD was observed in both atorvastatin (5.0 +/- 1.4 vs. 12.8 +/- 3.6%, P < 0.001) and lisinopril groups (5.0 +/- 1.2 vs. 11.4 +/- 5.0%, P < 0.001). Partial significant enhancement was observed in placebo group (4.9 +/- 1.1% vs. 5.7 +/- 1.0, P = 0.002). However, it was lower than the cutoff value for endothelial dysfunction. Conclusion: These findings suggest that atorvastatin and lisinopril improve endothelial functions in Behcet's disease patients. However, large studies are needed to determine the long-term effects of atorvastatin and lisinopril therapy. (Echocardiography 2010;27:997-1003).