Background: Hepatitis A infection is a common infectious disease in many tropical countries. Thailand is an endemic area of this disease. Recommendation of hepatitis A infection has been set in many countries. Objective: to determine if adults would benefit from hepatitis A vaccination in Thailand Methods: Here, we performed a cost-benefit analysis to find out the proper strategies for Thailand. Three strategies were tested in this study; a) no intervention, b) vaccination without screening and c) vaccination after screening. Review of the literature was performed in order to set the path probability of each strategy. Cost of each intervention was also identified. The outcome was assigned as the economical loss due to the possible hepatitis A infection for each strategy. Benefit was set as the final total cost according to each strategy (cost of intervention and economical loss due to the possible hepatitis A infection). Results: Of interest, the most benefit was got from the no intervention strategy. While the vaccination after screening was the worst strategy. Conclusions: Hence, we do not recommend hepatitis A vaccination for Thai adults.