Background and aims: Hepatitis B virus (HBV) infection is a public health problem and affects nearly 350 million people worldwide. The present study was conducted in order to investigate the role of circulating angiotensin-converting enzyme (ACE) in the context of renin–angiotensin–aldosterone in newly diagnosed chronic hepatitis B infection. Moreover the association between liver fibrosis and serum ACE levels was also investigated. Materials and methods: The study was performed on 50 chronic hepatitis B (CHB) patients (24 males, 26 females; median age 39.4 years, range 18–63) and 20 healthy controls. The clinical features of CHB patients including demographics, laboratory and liver biopsy findings were summarized. Serum ACE levels were measured by using commercially available kits. Results: Serum median ACE levels were 48.4 (14–83) U/L and 26.2 (12–48) U/L for the CHB patients and controls, respectively. Serum ACE levels were significantly higher in patients with CHB compared with the control group (p2) and 28 patients (56%) had mild liver fibrosis (Ishak score ≤ 2). Mean serum levels of ACE were significantly higher among patients with advanced fibrosis as compared with those without advanced fibrosis (60.3±14.2 U/L vs. 39.0±10.5 U/L, p