Lathrolestes nigricollis (Thomson) and Grypocentrus albipes Ruthe, Palearctic specialist parasitoids of the birch-leafmining sawfly Fenusa pusilla (Lepeletier), were imported from central Europe and released at three locations in Edmonton, Alberta, Canada during 1994-1996. Parasitoids became established at two locations, L. nigricollis at both and G. albipes at one, and were recovered for 3-5 years after release. Lathrolestes nigricollis has dispersed throughout most of Edmonton, and at least 13 km from release sites, but G. albipes has been recovered only 400-500 m from one release site. Five years after introduction at one site, percent parasitism by L. nigricollis was 78% and 84% for the first and second generations, respectively, and about 48% of parasitoid eggs were encapsulated. none