Four Old World blow flies (Diptera: Calliphoridae), Chrysomya albiceps (Wiedemann), C. putoria Wiedemann, C. megacephala (Fabricius), and C. rufifacies (Macquart), have recently invaded the New World. The interaction of Chrysomya rufifacies (Macquart) with native carrion flies in Texas, USA, was investigated by reducing oviposition by the invader on rabbit carcasses outdoors. These carcasses produced significantly more Cochliomyia macellaria (Fabricius) adults compared to carcasses on which the invader was not reduced. The results suggest that C. macellaria populations will decline where the two species co-occur. They also support the hypothesis that the carrion community is saturated with species, and provide a mechanism for the possible elimination of Lucilia caesar (Linnaeus) in Madeira and the reduction of C. macellaria in South America by Chrysomya albiceps (Wiedemann).