This article describes a project that established continuous quality improvement efforts in outpatient pharmacy services. Using the Six Sigma methodology, a measurement-based strategy that focuses on process improvement and variation reduction, the investigators examined a series of such processes in home-delivery pharmacy. Discussion includes a process map of 13 identified indicators that contribute to medication errors and how each of these were defined, measured, analyzed, and improved. The authors conclude that initial improvement efforts may create a perception of declining quality, but these early findings represent the necessary steps in effective quality improvement projects.