After the research of literature, only Furterer and Elshennawy (2005) was found as a Lean Six Sigma application made in public. In this study made in the finance department of a city, process improvement opportunities were defined by forming process flow map. Then the improvement plan was prepared and the cost benefit analysis was evaluated with solutions. At the end of the study, wage payroll preparation process was decreased by 60%, purchasing and payment process by 40% and the process of getting account by 90%.