In recent years, the high demand for methods to satisfy process plants performance requirements has shed the light on the subject of process control. This subject has become increasingly important as a result of the large emphasis placed on environmental and safety regulations, plant efficiency and economic factors. The primary objective of process control is to maintain a process at the desire operating conditions safely and efficiently, while satisfying environment and product quality requirements . The nonlinear nature of these processes requires other methods than conventional control. Fuzzy controllers are a practical alternative for such processes and provide human experts the ability to control the process by having intuitive understanding of it. Fuzzy controllers are knowledge-based controllers and do not involve or require a mathematical model of the process throughout its design and implementation. This paper addresses the application of fuzzy control to a continually stirred tank reactor (CSTR). The paper demonstrates the feasibility of this method in light of a highly nonlinear chemical process as such.