Over the last few years, the number of organizations that deliver information technology (IT) services is increased. There are some frameworks such as Information Technology Infrastructure Library (ITIL) for IT Service Management that consists of a set of guidelines that specify what an IT organization should do. However, they don’t explain how to do it. For example, they specify that IT should allocate a priority for each incident that comes into the service desk, but they do not specify how to allocate those priorities. Six Sigma defines a process improvement approach that is based on statistical measurement, drives quality improvement, and reduces operational costs that companies such as Motorola, Allied-signal and General Electric have used to produce millions of dollars in bottom-line improvements. It helps in developing detailed work instructions, and it defines a methodology for continually mapping, measuring, and improving the quality process. Six Sigma can help to determine, how an IT organization manages its services in order to increase the quality of IT delivery processes. Our objective in this article is to improve the quality of Information Technology Service delivery and support processes with Six Sigma.