It is an accepted fact that no system is perfect from the viewpoint of performance. Problems pertaining to performance affect all types of systems, regardless as to whether they are client/server or Web application systems. It is imperative to understand the factors affecting performance of the system before embarking on the task of tackling them. The constraints affecting the performance may be many but can be broadly classified into (i) technical and (ii) project related factors. The former is very much pronounced in the case of Web-based systems, as the relevant technology has not attained the stage of maturity to address the issues on its own. On the other hand, the project managers struggle to develop an optimal system within the existing technology framework. This in turn, generates many project related factors sub optimizing the performance. Likewise, many factors affecting the performance of the system are discussed in this chapter. The subsequent chapters deal at length with the methods and strategies to tackle these factors.