Rhyssocolpus vinciguerrae sp. n., from natural habitats in Iran, is described, illustrated and sequenced. It is characterised by the body length of 1.04-1.37 mm, lip region offset by depression and 11-13 μm broad, odontostyle 8-10 μm or 0.7-0.8 times the lip region diam. long, neck 227-265 μm long, pharyngeal expansion 80-95 μm long or 31-35% of total neck length, a dorsal cell mass present between cardia and the end of the anterior ovary/testis, uterus bipartite, 90-170 μm long, vulva longitudinal (V = 48-55), abundant irregularities in body cuticle around vulva, female tail conical with rounded terminus (35-55 μm, c = 24-34, c′ = 1.4-1.9), spicules 43-51 μm long and 6-8 spaced ventromedian supplements located outside the range of the spicules. It is very similar to R. aquilonius, R. arcticus and R. iuventutis. A molecular characterisation of the new species was done on ribosomal DNA nearfull-length small subunit 18S gene, internal transcribed spacer and partial 5.8S gene. The results obtained support a close relationship between Rhyssocolpus and Heterodorus, and a more distant relationship with Enchodelus.