Gastric cancer is one of the most common cancers in the world, following lung, breast and colorectal cancer.1-3 Risk factors of gastric cancer include poor diet, smoking, family history, inflammation, and Helicobacter pylori infection.4,5 Epide- miological studies have shown that diet including antioxidant nutrients plays an important role in prevention of cancer development.6,7 Especially, consumption of lycopene reduced risk of several cancers.8-10 However, compared to other cancers such as prostate cancer, anticancer effect of lycopene in gastric carcinogenesis has not been well studied. Lycopene is thought to be the active component in red fruits and vegetables such as tomatoes. In addition to its potential anticancer activity, lycopene supplementation decreased the occurrence of chronic diseases including type 2 diabetes, osteoporosis, and coronary heart disease.11 Since lycopene has 11 conjugated double bonds, it functions as the most potent antioxidant among carotenoids.12 Therefore, lycopene prevents the oxidative damage of DNA, lipids and proteins.13 Other potential mechanisms of lycopene include cell cycle arrest, modulation of immune function, and