EN
Entomopathogenic nematodes (EPN) of the families Steinernematidae and Heterorhabditidae were isolated from 57 of 91 localities in northern Poland. Of 489 soil samples collected in the field, EPNs were recorded in 27 per cent of them. Steinernema species were more frequent than Heterorhabditis: five of the family Steinernematidae and two of the family Heterorhabditidae were identified. Nematodes S. feltiae was the most frequently recorded species in different ecosystems. There were two rare of entomopathogenic nematodes species to the Polish fauna: S. silvaticum (only in natural ecosystems) and S. bicornutum (only in agrocoenoses). It seems that the presence of a suitable host in the environment is the most important factor for EPNs. Simple PCR-RFLP system was used to differentiate eight EPN species.