A survey of intestinal parasites was performed in South Vietnam. Samples were collected from 717 Vietnameses, 1,933 U.S. Forces, 433 stool specimens of Korean Troops in South Vietnam. And 114 of Korean Army patients in home land were also examined as a control. Findings were discussed with others and summarized as follows: 1)A parasitic rate, incidence in general, was 44.8 %. 2)Koreans in South Vietnam showed 82.4 % of infection rate, Vietnamese 64.6% and U.S. Forces 26.1 %. Korean home patients revealed 93.9 %. 3)Following 10 species of helminths ova and 5 kinds of protozoa were found: Ascaris lumbricoides, Hookworm, Trichocephalus trichiurus, Strongyloides stercoralis, Trichostrongylus orientalis, Enterobius vermicularis, Metagonimus yokogawai, Clonorchis sinensis, Hymenolepis nana, Taenia sp., Entamoeba histolytica, Entamoeba coli, Endolimax nana, Giardia lamblia and Trichomonas hominis. 4)The incidence of Ascaris lumbricoides among Koreans in South Vietnam was 15.9 %, much less than Korean home patients. 5)The infection rate of A. lumbricoides in Saigon residents was 47.2% but in Chulai 36.8% and in Quinhon 35.8 %. 6)Trichocephalus trichiurus was most frequently found in Koreans. 7)Quinhon residents showed 78.7 % positive in hookworn infection and Chulai 24.7 %. In Saigon, on the contrary, infection rate was only 3.1 %. 8)No Strongyloides stercoralis, but two cases of Trichomonas hominis were found among Koreans in South Vietnam. 9)U.S. Forces showed higher incidences than Koreans and Vietnameses in the incidences of Entamoeba histolytica and Endolimax nana. 10)Most of the U.S. Forces revealed single infection. Korean home patients showed the highest per centage of polyparasitism. 11)Non-autochthonous infections in Korea could not be found among Koreans in this survey.