We investigate the piezoelectric response of piezoelectric-rubber consisting of lead zirconate titanate (PZT) particles and silicon rubber prepared by holding it at 100°C for 60 min. Two types of piezoelectric-rubber were used; one was mixed with PZT particles forming linear aggregates, and the other was mixed with PZT particles forming a random dispersion. The piezoelectric-rubber whose PZT particles were aligned normal to the rubber surface had much higher piezoelectric effect than the type of piezoelectric-rubber whose PZT particles were randomly dispersed. The reason for this is that force applied on the former is directly transmitted to PZT particles and the electric charges generated from PZT particles had higher mobility because of the aligned PZT particles, which were connected with each other. As a result, the formation of linear aggregates of PZT particles in rubber was effective in enhancing piezoelectric properties of piezoelectric-rubber. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 39862.