Background: If the pepsinogen (PG) level could indicate the condition of the gastric mucosa, it can rapidly diagnose atrophic gastritis, a high risk factor for stomach cancer. Based on varying distribution and location of secreted cells of PG I and PG II, this study aimed to determine the correlation between gastroscopy findings and PG levels. Methods: From January to December 2018, gastroscopy findings in 103 subjects were compared according to PG I, PG II, and PG I/II ratio, with adjustments for sex, age, body mass index, underlying diseases, family history of stomach cancer, and social history. Results: The group with atrophic gastritis had a significantly higher PG II value and a significantly lower PG I/II ratio than the control group. Those with a higher Los Angeles classification of reflux esophagitis were observed to have higher PG I and II levels, although this finding was not statistically significant. In cases of heartburn, duodenitis, intestinal metaplasia, and Helicobacter pylori infection, PG I and II levels were low, but not statistically significant. Conclusion: After adjusting for the characteristics of subjects, a low PG I/II ratio was found to be a useful predictive factor for atrophic gastritis.