Whilst investigating plant-parasitic nematodes in Urmia City, West Azerbaijan, Iran, soil samples were collected from the rhizosphere of willow trees (Salix babylonica) known to have a population of cyst nematodes. Morphological, numerical and molecular approaches revealed that this population represented the willow cyst nematode, Heterodera salixophila, the first report of this species from Iran. Reproduction of the nematode on S. babylonica was confirmed by inoculating 5000 viable eggs and second-stage juveniles (J2) per kg soil on 2-year-old seedlings of S. babylonica grown in pots containing sterilised soil and incubated under glasshouse conditions. Principal Component Analysis (PCA) and hierarchical cluster analysis of morphometric characters of J2 and vulval plates of species within the Humuli group supported the separation of H. salixophila from other species in this group. In the ITS-rRNA phylogenetic tree, the Iranian population of H. salixophila formed a cluster with two other populations of the species from Belgium and Ukraine, while in the D2-D3 expansion segments of the 28S rRNA tree, it grouped with a population from Belgium as a basal clade in the Humuli group.