Targeted surveys were conducted for the entomopathogenic nematode Heterorhabditis in areas of Denmark, Estonia and Hungary. Isolateswere identiŽ ed by IEF, PCR and cross-fertilitytests as belonging to three distinct taxonomic groups: H. bacteriophora, the north-west European (NWE) type of H. megidis and the Irish type of Heterorhabditis. The Irish and NWE types of Heterorhabditis were both present in Denmark (at six and four sites, respectively),while only the NWE type was recovered in Estonia. H. bacteriophora was the dominant heterorhabditididentiŽ ed in Hungary (ten sites), but the Irish typewas also detected at two sites. This is the Ž rst report of the Irish type of Heterorhabditis on continental Europe. Co-occurrence of two Heterorhabditis types at a single site was noted in Denmark (Irish and NWE) and in Hungary (Irish and H. bacteriophora). Heterorhabditiswas recovered at 38.5% of sites (n = 26) in Denmark (north coast of Sjælland), 27.3% of the coastal sites (n = 22) in Estonia, and 32.6% of sites (n = 46) in Hungary.