The purpose of this paper is to outline, very briefly, the application of simulation techniques to Computer Performance Evaluation (CPE) problems. It covers situations where the use of simulation is appropriate and some cases when it is not. It also includes a discussion of the types of questions simulation can help to answer and how to go about finding the answer.It must be kept in mind always that simulation is a part of the larger world of CPE, in general. The other elements are hardware monitoring, software monitoring, statistical analysis, benchmarking and other analytical tools. Each of these tools has its strengths and weaknesses and must, therefore, be properly applied. Another factor to keep in mind is that the use of these tools is not mutually exclusive, i.e., they should be used to complement each other whenever appropriate rather than totally by themselves. This discussion deals with simulation as <u>a</u> CPE tool, not <u>the</u> CPE tool. More and more, the various tools are being used together to find solutions to problems. Some of these instances will be brought out in the discussions to follow.