Aphidius colemani Vier. (a Chilean strain) was introduced and became established in the field between 1992 and 2000 in the Czech Republic. The target aphid species, Aphis spiraephaga Muell. on Spiraea ornamentals, and later the Russian wheat aphid, Diuraphis noxia (Kurdj.) on small grains were found parasitized, but an increasing number of other host aphid species in various urban ecosystems, crops and native communities was also detected. The establishment of A. colemani is classified as positive in supplementing the native parasitoid guilds as well as in contributing to the overall biodiversity of hymenopterous parasitoids in the cultivated landscape. none