Reiki healing is one of several complementary and integrative therapies becoming increasingly prevalent in mental health counseling. It has been identified in the medical field for its usefulness in treating anxiety, depression, distress, and pain but has rarely been studied for its counseling impact on client wellness. I conducted single-case research to explore psychotherapeutic Reiki's (PR's) influence on adult clients' anxiety symptoms and perceived sense of mindfulness and provided analysis of data collected from two assessments administered weekly: the Adult Manifest Anxiety Scale-Adult and the Mindful Attention Awareness Scale. Three of the four participants demonstrated significant improvement in both anxiety and mindfulness over the course of the PR intervention. The study revealed potential therapeutic benefits for integrating PR with conventional talk therapy. Included in discussion of study results are clinical implications and importance, suggestions for future research, and limitations. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]