Six Sigma is a business strategy that seeks to identify and eliminate causes of errors or defects or failures in business processes by focusing on outputs that are critical to customers. It is a measure of quality that strives for near elimination of defects using the application of statistical methods. A defect is defined as anything which could lead to customer dissatisfaction. The fundamental objective of the Six Sigma methodology is the implementation of a measurement-based strategy that focuses on process improvement and variation reduction. This article lists some pros and cons of Six Sigma.