Lung fluke disease or Paragonimiasis is caused by Paragonimus genus. In Vietnam, this disease occurs in 10 provinces in the northern border and P. heterotremus is the only pathogen. Today, identification of Paragonimus lung fluke is almost based on morphology and pathogenic properties in experimental animals, beside that, morphological and molecular phylogenetic study based on sequences of ITS2 and a part of coxl genes are also performed for detection and identification. NAD1 is a potential marker in identification and phylogenie analysis. Using specific primer pair PHE13F-PHE14R, a 1,7 kb DNA ftagment containing the entire NAD1 gene of P. heterotremus was amplified by PCR reaction. PCR product was, cloned into PCR2.1 TOPO vector and sequenced. NAD1 sequence of P. heterotremus is 906 bp, which was used for comparative and phylogenetic analysis with those NAD1 of other flukes. As results, the homology of NAD1 between P. heterotremus and P. ohirai is 81 percent in nucleotide and 86 percent in amino acid
between P. heterotremus and P. westermani is 75 percent in nucleotide and 82 percent in amino acid. In phylogenetic analysis, P. heterotremus, P. ohirai and P. westermani are placed in the paragonimid group, others in the opisthorchiid or fasciolid groups.