In this work morphological and molecular variability of seven populations of Jensenonchus sphagni (Brzeski, 1960) from Vietnam and Poland were studied. As a consequence, hereby we report the first occurrence of this species in Vietnam and at the same time in the Asian continent. The first report and description of males of this species are also provided. Additionally, the small and large subunit ribosomal DNA (18S and 28S rDNA) and the mitochondrial cytochrome c oxidase subunit I (mtCOI) sequences were acquired for the first time for this species and genus. Moreover, the obtained results of the phylogenetic analyzes question the current systematic position of J. sphagni and suggest its transfer from the subfamily Iotonchinae (fam. Iotonchidae) to the subfamily Prionchulinae (fam. Mononchidae).