Coronary angiography is an invasive imaging technique that directly visualizes the anatomical structure of the coronary arteries and is considered the gold standard for diagnosing significant coronary artery disease. In the post-coronary angiography period, alleviating pain and enhancing patient comfort are important goals of clinical care. Reiki is an energy-based complementary therapy aimed at supporting the body's natural healing processes and promoting relaxation. Among non-pharmacological interventions, Reiki-a practice rooted in Traditional Chinese Medicine and meaning universal life energy-is a safe, cost-effective, and easily applicable method. Studies have shown that Reiki is effective in reducing pain, anxiety, fear, and stress, as well as in improving comfort and holistic well-being. This study was designed to examine the effects of Reiki therapy administered after coronary angiography on patients' levels of pain and comfort.