The species composition and abundance of coprophilous predatory Staphylinidae in two sites of temperate and subtropical Argentina are presented and discussed in terms of their hypothetical effect on the dung breeding fly community. Specimens of Staphylinidae were collected from cow manure by flotation. Dung breeding fly puparia were also collected to obtain parasitoidal Staphylinidae. Roughly the same number of species, and the same species of common staphylinids were found in both sites. Also, the dominant species were almost the same: Philonthus pauxillus Solsky, P. flavolimbatus Erichson, and Aleochara verberans Erichson. However, Philonthus sp. 1, and Aleochara notula Erichson were very abundant in Buenos Aires, but rare in Tucumán, and Philonthus nv. sp., was common in Tucumán but not found in Buenos Aires. Of the parasitoid species in the genus Aleochara Gravenhorst, A. notula was recovered from Oxysarcodexia varia (Walker), Sarcophagula occidua (F.), and Palaeosepsis discolor (Bigot) (Sepsidae). A. verberans from O. varia, Oxysarcophaga aurifinis (Walker), and Ravinia sueta (Wulp). A. puberula from O. varia, and A. bimaculata from O. aurifinis. All the hosts, except P. discolor, were in the family Sarcophagidae. Specimens of Philonthus Stephens were the most abundant predatory rove beetles, and field and laboratory data suggest they are the group of predators that most affect the community of dung breeding flies. The necessity for the release of exotic predatory Staphylinidae in Argentina is discussed.