Background: Coronary artery disease (CAD) is a primary cause of death worldwide. CAD negatively affects individuals because it reduces their functional skills and self-care abilities and disrupts quality of life. Purpose: This study was designed to assess the impact of a training program based on Orem's self-care deficit nursing theory (SCDNT) on self-care abilities and quality of life in patients with CAD. Methods: This study was conducted using a randomized, controlled, pretest/posttest experimental design. One hundred two patients with CAD were divided evenly into either the intervention or control group, with sample randomization based on gender, age, low-density lipoprotein cholesterol level, and Self-Care Agency Scale scores. For both groups, interviews were conducted in two sessions held, respectively, at the hospital and at home. Study data were collected using the patient information form, Self-Care Agency Scale, MacNew Heart Disease Health-Related Quality of Life Questionnaire (MacNew), Quality of Life Questionnaire (15D), and training booklet. Results: A highly significant difference was found between the two groups in terms of the average posttest scores on the Self-Care Agency Scale, MacNew, and 15D. For the intervention group, the posttest scores on the Self-Care Agency Scale, MacNew, and 15D were significantly higher than the pretest scores, whereas average pretest and posttest scores on these measures were similar for the control group. Conclusions: The training program developed in this study based on Orem's SCDNT improved self-care agency as well as disease-specific and overall quality of life in patients with CAD. Nurses should pay attention to the CAD-related educational level of patients when teaching them how to live with their disease. Moreover, nurses should use Orem's SCDNT to strengthen the self-care agency of these patients to increase quality of life and the effectiveness of related education efforts. Finally, medical institutions and governments should develop appropriate education policies for patients at risk of CAD and for those with CAD.