The six sigma methodology have an important place for developing and reducing the actions which do not have inner process in
supply chain in the firms. The aim of six sigma is defining, analyzing, correcting and improving the variables, which affect the
quality of supply chain process in order to decrease the number of defects and the failures and to propose the improvement
means for the processes. In this study general structure of six sigma is explained with regard to 'how to define the complex
problems which are encountered in the supply chain' along with the relevant knowledge and comments for statistical methods
that are utilized in measurement and analysis of supply chain.