This is a cross sectional study for the role of serum leptin in 30 patients with liver cirrhosis and HCC (Group 1), 30 patients with liver cirrhosis (Group 2) and 30 controls ( Group 3). Questioner and investigation showed that HCC had no significant higher age than cirrhosis and male gender was more associated with HCC (26 ̸ 30, 86.7%) than cirrhosis (22 ̸ 30), 73.3% P= 0.4). In comparison to cirrhosis group, HCC group had lower body mass index (BMI) (P= 0.005) more frequent jaundice and hepatomegly, prolonged PT, more frequent Child class C and higher s AFP (P = 0.05, 0.02, ˂ 0.001 respectively). Serum leptin was significantly higher in cirrhosis and HCC than controls (P ˂ 0.001) and tend to be significantly higher in HCC group than cirrhosis group (P = 0.07. As a diagnostic marker for HCC, serum leptin has area under curve (AUC) 79.9± 9.1 9 (P ˂ 0.001) which is good but less than AFP (97± 2.5, P˂ 0.001). In conclusion, serum leptin is increasing in liver cirrhosis and HCC, which may suggest its role in fibrogenesis and angiogenesis and probably as a diagnostic marker for HCC.