Longidorus behshahrensis n. sp. is described and illustrated using morphological and molecular data. It was recovered from the rhizosphere of a wild cherry tree in Mazandaran province, northeastern Iran. The new species is characterized by having 6.8-8.4 mm long females, lip region separated from the rest of the body by a shallow depression, amphidial fovea pocket shaped not bilobed, guiding ring at 25-31 µm from the anterior end, 81-91 and 51-63 µm long odontostyle and odontophore, respectively, 109-130 µm long pharyngeal bulb, didelphic-amphidelphic reproductive system with long tubular bipartite uteri with sperm, vulva at 44-54%, tail bluntly conical, dorsally convex, ventrally concave with widely rounded terminus, hyaline region with discernible radial lines; males common with 50-60 µm long spicules and 9-11 ventromedian single supplements. Only the two latter juvenile developmental stages were recovered for the new species. Codes for identifying the new species are A3-B1-C23-D2-E1-F34-G23-H2-I2. Morphologically, the new species comes close to eight known species of the genus namely L. artemisiae, L. dunensis, L. elongatus, L. euonymus, L. goodeyi, L. iranicus, L. protae and L. tabrizicus. The morphological differences of the new species and the aforementioned species are discussed. In molecular phylogenetic analyses using LSU rDNA D2-D3 sequences, the position of the new species among closely related species was not resolved due to polytomy. In ITS1 phylogeny, the new species formed a clade with L. distinctus.