Piperonyl butoxide was given in the diet to provide levels of 0 (control), 0.02%, 0.06%, and 0.18% from 5 weeks of age of the F0 generation to 12 weeks of age of the F1 generation in mice. Select reproductive and neurobehavioral parameters were then measured. In exploratory behavior in the F0 generation, vertical time of adult females increased significantly in a dose-related manner. In behavioral developmental parameters, cliff avoidance was delayed significantly in the high-dose group in male offspring, and this effect was significantly dose-related. In female offspring, surface righting was significantly delayed in the high-dose group, and this effect was significantly dose-related. In spontaneous behavior in the F1 generation, females showed more activities in some variables in the high-dose group. Dose levels of piperonyl butoxide used in the present study produced several adverse effects in neurobehavioral parameters in mice.