Purpose: The purpose of this study was to identify the degrees and relationships of disease-related knowledge, depression, family support and health behaviors of older patients with coronary artery disease, and the factors influencing their health behaviors. Methods: The subjects included 139 older patients with coronary artery disease who visited the outpatient clinic at one general hospital located in metropolitan city B. Data collection was performed from December, 2018 to February, 2019, using a structured self-reported questionnaire. Descriptive statistics, t-test, one-way ANOVA, Pearson correlation coefficients, and multiple linear regression were used to analyze the data. Results: Disease-related knowledge (r=-.17, p=.050) and depression (r=-.32, p<.001) had significant negative correlations with health behaviors. While, a significant positive correlation was noted between family support and health behaviors (r=.67, p<.001). In the final multiple regression analysis, medication intake status (β=-.17, p=.009), depression (β=-.15, p=.017) and family support (β=.61, p<.001) significantly influenced health behaviors of the subjects. The explanatory power of the subjects’ medication intake status, disease-related knowledge, depression and family support on health behaviors was 49.0% (F=33.97, p<.001). Conclusion: Developing an effective program to improving medication status, depression, and family support is recommended for the enhancement of their health behaviors and ultimately for their recovery and well-being.