Despite a slow decline in the incidence of gastric cancer over the last 90 years, we can still expect to see over 100,000 patients die of this disease each decade in England and Wales. The 5-year survival rate has not improved during this century, which is largely due to the stage at diagnosis being unchanged. There are a number of prognostic determinants in gastric cancer which have clinical relevance. Age is an important determinant; patients under 40 years commonly have more advanced diffuse lesions than older patients so that a higher index of suspicion needs to be maintained in younger patients with persistent symptoms. Conflicting reports make it unclear whether the duration of symptoms bears any relationship to tumor stage, but there is some evidence that actively shortening the symptom duration by early investigation can have a beneficial effect in the proportion of patients diagnosed with early cancers. The site of the tumor is important; unfortunately, the proportion of patients with cardia lesions is increasing and this has had the effect of reducing the overall survival. Tumor size should not play a part in the decision to resect a lesion as most studies show no clear relationship between tumor size and stage. Tumor stage is the most important prognostic determinant and efforts to increase the proportion of stage I cancers presenting for surgery can be shown to alter the natural history of the disease, by diagnosing it when it is still surgically curable.