This chapter explains how the successful theories about process integration can be implemented in different industrial fields by introducing a rigorous methodology. Starting from the consideration that processes must be managed to achieve customer satisfaction, the companies necessitate changing their old paradigms and focusing on an integrated management of their functions. In this chapter, the proposed solution is the Six Sigma methodology. It can be applied to every industrial field, anywhere the need for a global, shared objective and improvement is advised. To better show the opportunities and advantages, due to the implementation of Six Sigma in business strategies and activities, three case studies are discussed.