Current trends in semiconductor manufacturing place a large emphasis on monitoring and/or controlling costs. One of the tools used in this effort is cost of ownership modeling. Cost of ownership provides a method to monitor and control costs, evaluation projects, and gain a better understanding into the manufacturing process. From the previous literature on the subject, models can range from very simple to very complex. The need for complexity in this type of model must be evaluated with respect to the actual level of accuracy required. Quality of the data obtained is very important as inaccurate information can lead to potential misuse. From past experience, data collection for modeling can range from being easily accessible to very obscure. In the search for data, various departments such as finance, engineering, facilities, production, and many others must be consulted. the value of the information obtained versus the cost involved in obtaining this information must also be evaluated. In this paper, the development of a cost of ownership model is outlined with the emphasis being placed on the desired goals, the methods used, the sources and manipulation of the data, and a practical example. Future applications of cost of ownership modeling are also discussed as well as integration into a semiconductor production facility.