Objectives The current study aimed to examine the cross-sectional association between shift work and gastritis using endoscopic evaluation. Methods We collected questionnaire data from 964 non-shift workers and 290 shift workers aged 22-40 years at an electronics company, comprising age, smoking status, alcohol consumption, physical activity, occupational stress, and gastrointestinal symptoms. We performed a gastroendoscopy of participants. Along with describing the gastroendoscopic results, we analyzed the correlations between gastritis and shift work using multiple logistic regression analysis. Results In terms of gastrointestinal symptoms, night shift workers complained more of indigestion than non-shift workers (P<0.01), and the rate of gastritis was higher. The odds of gastritis was significantly higher among shift workers after adjusting for covariates. The odds ratio (OR) for gastritis was 2.24 [95% confidence interval (CI) 1.47-3.43] in shift workers compared with non-shift workers. Among seven subtypes of gastritis, only superficial gastritis was significantly associated with shift work (OR 1.58, 95% CI 1.12-2.24). Conclusions We found that shift workers experience gastritis more than non-shift workers as well as more gastrointestinal symptoms, particularly indigestion. Using endoscopic findings, our study supports that shift work negatively affects the gastrointestinal system.