Serum pepsinogen (sPG) is a marker of gastric mucosal atrophy, a condition that has been associated with an increased risk of gastric neoplasia. A low sPGI level and a low PG I/II ratio have been associated with severe gastric atrophy, and are frequently found in gastric cancer. Because the prevalence of gastric cancer is high in Korea, it would be convenient if a good biomarker for gastric cancer were developed. Two studies recently investigated the efficacy of sPG along with Helicobacter pylori (H. pylori) as a screening tool for gastric cancer. In these studies, sPG was measured using a Latex enhanced Turbidimetric Immunoassay. We found that H. pylori IgG status, age and gender were associated with serum pepsinogen levels. Thus, to increase the ability of the PG I/II ratio to detect atrophic gastritis, the cutoff value for the PG I/II ratio should be stratified according to the H. pylori IgG status. In addition, a PG I/II ratio (< or =3.0), which has been widely used as an international standard for gastric cancer, was found to be a reliable marker for the detection of gastric dysplasia or gastric cancer, especially of the intestinal type. The efficacy of the test in Korea was lower than the efficacy in Japan. However, the detecting power of a PG I/II ratio (< or =3.0) was significantly increased in the presence of H. pylori. The ratio together with H. pylori psotivitiy could provide a means of identifying persons at high risk of developing gastric cancer in Korea.