In the last decade a process improvement technique, known as Six Sigma, is implemented by many pioneers of the industry as an approach used to more productive and increase profits in all business process from production to human resources management, from finance to marketing.

The companies would like to keep and improve their position in a daily changing world market while new techniques and concepts are introduced to the global markets every day and this is only possible through continuous improvements and breakthroughs. In this study, it has been presented the six sigma practice of a power plant owned by Enerjisa, a major energy company in Turkey. In order to achieve Six Sigma project targets, quality techniques and statistical techniques (hypothesis testing, design of experiment etc.) are used.

Keywords:Six Sigma, Quality, DMAIC