Objective: This quasi-experimental research designed was to evaluate the effects of a program for health literacy development among pre-diabetic mellitus in municipal area of Nakhon Si Thammarat Province, Southern Thailand. Methods: This quasi-experimental research designed was to evaluate the effects of a program for health literacy development among pre-diabetic mellitus in municipal area of Nakhon Si Thammarat Province, Southern Thailand. It was used the one group pretest posttest design 114 sample groups were selected according to voluntarily from the pre-diabetes mellitus group in the community. The experimental group received program for health literacy development the concepts and theories, the KAP model is used in 12 weeks. Data analysis used descriptive statistics, the chi-square test and the paired t-test. Results: A total of 114 questionnaires were analyzed. The results revealed that after participating in the program, the level of health literacy, self-efficacy related to management, and health behaviors reported by the experimental group was higher than pre experimental at the significance level of 0.01. The blood sugar level of the experimental group was also significantly lower than pre experimental (p < .05). The findings suggest that improving health literacy is a strategy that can help pre-diabetes mellitus acquire appropriate health behaviors and can decreasing the diabetes mellitus in community. Conclusion: The intervention in the present study, was significantly effective on knowledge and attitude in pre-diabetes mellitus.