This article describes an exploratory social work study that examined the efficacy of cognitive- behavioral treatment of perfectionism. A single-system design was used to analyze change due to the intervention. Three instruments, two standardized and one self-anchored, were used to collect data across the phases of the ABA design. The study was replicated with nine clients. Analysis of the data indicated that the clients experienced a considerable reduction in their levels of perfectionism as a result of the cognitive-behavioral intervention. The results also indicated that several issues were associated with perfectionism, including issues such as self-criticism, difficulty in dealing with feedback, procrastination, and unrealistic goal setting. Consideration was given to the limitations of the study as well as its applications to social work practice and research.