This study was designed to identify the relationship between preventive behavior and health belief about Hepatitis A among young adults. Methods: The sample consisted of 197 participants between the ages of twenty and forty. The data were collected from May 3 to May 30 2011 and analyzed using descriptive statistics, t-test, x2 test, and Pearson correlation coefficients. Preventive Behavior"s Scale about Hepatitis A and Health Belief"s Scale about Hepatitis A were used for data collection. Results: The mean scores of health behavior (2.97±0.34) and preventive behavior (2.46±0.30) about Hepatitis A were about average degree. The participant"s characteristics with preventive behavior were significantly different according to type of residence (x2=4.74, p =.040), experience of obtained knowledge about Hepatitis A (x2=5.68 p =.018) and attitude about Hepatitis A (x2=15.20, p<.001). Significant correlations were found between health behavior and preventive behavior with Hepatitis A (r=.20, p =.005). The preventive behavior had a significant positive correlation with susceptibility (r=.22, p =.001), severity (r=.17, p =.015), and benefit (r=.32, p<.001) towards Hepatitis A as the details of the health belief. Conclusion: These findings indicate that health belief may be necessary to improve compliance with preventive behavior on Hepatitis A among young adults. It is necessary to develop the strategy of reinforcing health belief in complying with preventive behavior for preventing the occurrence of Hepatitis A.