Despite a recent decline in incidence, gastric cancer (GA) remains one of the leading causes of cancer death worldwide, especially in Asian countries. The most common stages in the progression to GA are atrophy and intestinal metaplasia (IM), which are collectively known as chronic atrophic gastritis. These conditions are principally caused by Helicobacter pylori (H. pylori) infection. As the first step, the risk for GA should carefully assessed by interview from patients, serological tests or endoscopic examination according to the status of H. pylori infection. Systematic endoscopy protocol is essential to detect GC at an early stage which is a curative disease. However, the endoscopic diagnosis of subtle changes in gastric mucosa is often difficult and may vary from benign erosive changes to superficial malignancy. Thus, as the second step, it is generally accepted in Japan that existence diagnosis, qualitative diagnosis and quantitative diagnosis should be endoscopically carried out during systematic endoscopy protocol, then the treatment strategy is finally decided. Recently, the number of cases that are difficult to detect by white light endoscopy (WLE) alone has increased in the era of H. pylori eradication. Image-enhanced endoscopy (IEE) for the clear visualization of malignant lesions may be more helpful. Consequently, the status of H. pylori infection can be endoscopically evaluated. Appropriate new endoscopic modalities have been developed to provide an expanded color range and helpful not only to assess the location and extent of atrophy and IM but also to detect featureless GC.