The age-adjusted death rate from stomach cancer has been on a downward trend during the past 25 years in Japan. During the same period, a gastric mass screening program has been continually and actively conducted throughout the country as a secondary prevention for cancer, aimed at reducing the mortality from stomach cancer through early detection. The number of examinees now amounts to over 5,000,000 a year. According to many studies to evaluate the effectiveness of the mass screening program, it is suggested that the gastric mass screening in Japan contributed toward reducing the mortality from stomach cancer.