INTRODUCTION: Regional health promotion center 1 covering an area of 8 provinces in the northern of Thailand, it was the area with the highest ratio of the elderly population and the ratio has increased every year accounting for 23.35 percent and 28.03 percent in 2019 and 2023, respectively. From the National health literacy survey in 2019, it was found that the elderly group had an average health literacy level of 53.29 percent and the elderly people had sufficient health literacy was 19.5 percent, which was the lowest value compared to other age groups. Therefore, have been taken to raise the level of health literacy among this group to have the ability to take care of themself, have desired behavior and continue to have good health. OBJECTIVES: 1. To study the health literacy of the elderly population in regional health promotion center 1. 2. To study the effectiveness of promoting health literacy in the elderly in regional health promotion center 1. METHODOLOGY: Observation study results the survey of health literacy in the elderly population in regional health promotion center 1 in 2019 and 2023 compares health literacy levels using statistical methods (t-test) to found relationships among factors affecting health literacy using Binary Logistic Regression statistics. RESULTS: The results of the study found that; the elderly people in regional health promotion center 1 had a health literacy level increased to 77.05 percent and the elderly people which had sufficient health literacy increased to 83.0 percent, and when compared to 2019, it was found that there were increase significant of statistically (P-value <0.001) . When separating by category, questions regarding access to reliable information (access ability skill) were found at 86.6percent, the questioning regarding understand health information (understanding skill) were found at 77.4 percent, and in the category of using information for decision (decision skill) were found at 78.5 percent .When comparing each category with last year's data In 2019 found that; there were increase significant of statistically (p-value <0.001). Important factors affecting adequate health literacy include religion, no underlying disease, access to health services and communication channels to received health information. CONCLUSION: The health literacy can be accumulated and increased in all groups, especially, vulnerable groups such as the elderly who had many limitations including education, economy, health, technological ability. If there was serious support from all society sectors to reducing inequality in society, it will increase to adequate health literacy until having the ability to take sufficient care of themself to be healthy and continue to have a better quality of life.