Although the global incidence of gastric cancer has been decreased dramatically in recent decades, it is the most common cancer in north and northwest Iran. The wide variation in incidence across different geographical areas and higher proportion of cardia cancer are two main characteristics of gastric cancer in Iran. Current investigations indicate that a high prevalence of H.pylori infection, high dietary intake of salt and smoking are the main environmental factors of gastric cancer in Iran. Gastroesophageal reflux disease is another contributing factor in populations with a higher incidence of gastric cardia cancer. While interventions on modifiable environmental risk factors should be considered as the main modality to reduce gastric cancer development, surveillance programmes for early detection of cancer in highly selected groups may increase overall survival rates in potential patients in this country.