PURPOSE: This study investigated the levels of health literacy, self-efficacy, self-management, and glycated hemoglobin (HbA1c) levels in older adults with diabetes to identify the relationships between these factors. PATIENTS AND METHODS: This descriptive study consisted of 162 elderly outpatients with diabetes at the departments of endocrinology of three general hospitals in J Province, South Korea. Data were collected using a structured self-report questionnaire between October 21 and November 16, 2019. The data were analyzed using SPSS/WIN version 23.0. RESULTS: Health literacy was positively correlated with self-efficacy (rs=0.64, p<0.001) and self-management (rs=0.44, p<0.001) and significantly negatively correlated with HbA1c levels (rs=-.42, p<0.001). Self-efficacy showed a significantly positive correlation with self-management (rs=0.65, p<0.001) and a significantly negative correlation with HbA1c levels (rs=-.30, p<0.001). Moreover, a significant negative correlation was found between self-management and HbA1c levels (rs=-.35, p<0.001). Hence, health literacy and patient self-management levels were associated with HbA1c levels in older adults with DM. CONCLUSION: Health education for community-dwelling older adults with diabetes should consider their health literacy levels. Moreover, measures to improve self-management abilities may be needed when developing educational programs for older adults with diabetes.