This study investigated the effect of acoustic pingers on the behavior of Burmeister's porpoise (Phocoena spinipinnis) in the vicinity of the Peruvian small-scale driftnet fleet. Over a 4-yr period (2009-2012), 116 control (without pingers) and 94 experimental (with pingers) fishing sets were observed, and porpoise acoustic activity around nets was recorded using passive acoustic loggers (C-PODs). In regions of preferred habitat associated with cooler (17-18 C), shallow waters (within the 100 m. isobath), the use of pingers lead to an 86% reduction in porpoise activity around nets. The results suggest that pingers are likely to be \effective at deterring Burmeister's porpoises from fishing nets, and given the vast capacity of this and other fleets in the region, may substantially reduce mortality.