Lung flukes of the genus Paragonimus cause paragonimiasis which affect human and animal health. The main reason of infection is due to ingestion of metacercariae from second intermediate host or juvenile flukes from paratenic host. Symptoms of lung fluke are more likely to be misdiagnosed with pulmonary tuberculosis or other pulmonary disease, producing difficulties to diagnose and treat the disease (Blair et al., 1999). In Vietnam, Paragonimus and paragonimiasis have been studied for more than 20 years (Vien et al., 1994; De et al., 1998-2003; Doanh et al., 2005-2013). To date, 7 Paragonimus species have been reported (Doanh et al., 2013). Of which, P. heterotremus is prevalent in the north provinces and P. westermani is prevalent in the north central provinces. Both species can infect humans. However, many issues of two species have not been unknown. Therefore, we conducted a study on “Lung flukes, Paragonimus heterotremus and Paragonimus westermani, in Vietnam: morphology, molecular biology and immunological diagnosis”