This paper provides a systematic procedure for designing fuzzy PID controllers. The fuzzy nonlinear mapping with respect to error, error change and rate of error change is analyzed to produce different fuzzy PID controller structures. The design procedure is identified as a two-level tuning problem. A parameter reduction procedure is presented to reduce the existing complexity of this two-level design. An equivalent linear controller is used to identify the equivalent fuzzy PID tuning parameters related to each structure thus enabling the use of conventional PID tuning heuristics.