Serum pepsinogen I and II levels have recently become popular as indicators of atrophic gastritis in epidemiological studies. Previous studies show a significant association between serum pepsinogen levels and endoscopically diagnosed atrophic gastritis. This study assesses the level of agreement between the degree of atrophic gastritis as assessed by endoscopic examination and by serum pepsinogen assays. Study subjects were 200 outpatients at Aichi Cancer Center Hospital, Nagoya, Japan, who were endoscoped between February and August 1995. Agreement of the degree of atrophic gastritis was assessed by endoscopic examination and by serum pepsinogen levels. Agreement in assessing the extent of atrophic gastritis between the two methods was 57%, and the presence of atrophic gastritis was 79%. Serum pepsinogen assays identify the majority of patients with atrophic gastritis, although they are less useful in assessing the degree of atrophy in detail.