The benzoylurea chitin synthesis inhibitor diflubenzuron was evaluated as a rodent feed-through for the control of immature stages of Phlebotomus papatasi Scopoli (Diptera: Psychodidae). The development and survival of second instars of P. papatasi larvae that were fed feces from Syrian hamsters, Mesocricetus auratus, that had been fed a diet containing 0, 8.97, 89.7, or 897 ppm diflubenzuron was evaluated. No pupation or adult emergence occurred when larvae were fed feces from hamsters that were fed diets containing diflubenzuron. The mortality of sand flies fed feces from treated hamsters was coincident with pupation of the controls, suggesting a specific effect on the larval-to-pupal molt. The results of this study suggest that a control strategy using rodent baits containing diflubenzuron for phlebotomine sand flies and zoonotic cutaneous leishmaniasis may be possible.