A confirmed diagnosis of human fascioliasis was rare in Vietnam until 1978 when two cases were reported in humans. Since 1997, we have confirmed 500 cases of human fascioliasis. The majority of cases come from the central provinces of Vietnam: Da Nang, Quang Ngai, Binh Dinh, Phu Yen and Khanh Hoa. Patients were treated in hospitals in Ho Chi Minh City. All had high peripheral blood eosinophilic counts (16-70%) and positive serology with Fasciola gigantica antigen with positive titers of 1/1,600 to 1/12,800. We are unsure whether this represents an endemic pattern of disease or whether improved specific laboratory tools now facilitate better diagnosis. It is also possible that with changes in environmental factors and in the number and breeds of herbivorous domestic animals, Fasciola is increasing in frequency and easily contaminates the food.