The concept of Process Analytical Technology (PAT) was formally introduced to the pharmaceutical industry in the 2004 FDA landmark guidance Pharmaceutical CGMPs for the 21st Century a Risked Based Approach. For drug innovators, PAT represents an opportunity to maximize yield and minimize the potential for quality issues in commercial manufacturing. The FDA has bundled these new concepts in with a new regulatory filing process called the Pharmaceutical Quality Assessment System. Lean and Six Sigma both share the same fundamental philosophy of applying a structured process for understanding the parameters and attributes that affect the process output of interest. The Six Sigma methodology provides an effective framework for the process characterization and optimization required by PAT that is superior to the use of statistical tools isolation. The classic Six Sigma DMAIC model provides a good framework for objective scientific inquiry and is typically used to improve existing processes.