The study aims were to detect and confirm introgressive hybridization of an Fasciola isolate from human. Nuleotide sequence of ITS-2 (362 bp) of the ribosomal intergenic region and a portion of cox1 (423 bp) revealed, that the FsphNA liver fluke isolate possesses "maternal" genetic heredity from F. gigantica, whilist "paterna" heredity belongs to F. hepatica. FsphNA, thus, is an intermediate form of hybridization between F. gigantica and F. hepatica, which is the result of a process of the introgressive hybridization occurred in the past. Finding of the introgressive hybridization in human Faciola in Nghe An has once again confirmed a novel genetically hybrid form of F. gigantica and F. hepatica, which is the cause for increasing severe infections among animals and human in Southeast Asia countries. This also gave rise to warn that taxonomic identification not only is solely based on morphological examination but also should be undertaken on genetic analysis, particularly, when working with the so-called "intermediate form" of Fasciola spp.