Purpose: The research aimed to investigate the factors affecting cancer preventive behavior among patients with early gastric cancer (EGC) who underwent endoscopic submucosal dissection (ESD). Methods: Data were collected from 126 patients who underwent ESD for EGC and who were recruited from a single university affiliated hospital, Seoul, Korea. The data were analyzed by descriptive statistics, independent t-test, one-way ANOVA, Pearson’s correlation coefficient, and multiple regression analysis. Results: The average score of cancer preventive behavior was 66.87±10.36 out of 90. Correlations between attitude toward cancer and preventive behavior regarding cancer were positive (r=.26, p=.004). Also, the regression analyses revealed that factors affecting cancer preventive behavior included perception of cancer screening, attitude toward cancer, and age. A history of drinking alcohol on the other hand was negatively related to cancer preventive behavior. The regression analyses explained 31% of variance (F=6.50, p=.037). Conclusion These results suggest that nurses should develop a program for risk groups (people who drink alcohol regularly, are under the age of 65 and who have poor self-health care after ESD). And such a program should include interventions to improve attitudes toward cancer and perception of cancer screening, and encourage physical activity.