Abstract: This work describes the design and the behavior of a fuzzy control system for a pneumatic actuator, aimed at controlling the piston position and at enabling the system to accurately follow desired reference trajectories. A non-linear model of the system and three increasingly complex versions of the fuzzy controller are described in this paper, with a different number of input variables. It is shown that the three-variable and the four-variable fuzzy controllers allow to accurately control the response of the system to a position step input and the four-variable fuzzy controller enables the system to follow a sinusoidal reference trajectory with great accuracy.