Abstract: During 1987 to 1989, a survey of human intestinal protozoa was carried out in Yunnan Province. Altogether 103 pilot sites of 28 counties were selected via stratified and clustered random sampling. Iodine direct smear method was applied for fecal examination of 53 061 residents. A total of 10 species of intestinal protozoa were identified from 103 sites, the major pathogenic intestinal protozoa and infection rates were as follows: Entamoeba histolyica 2.5% , Giardia lamblia 2.5%, Blastocystis hominis 7.0%, Entamoeba coli 6.2%; Entamoeba hartmanni 2.1%, Endolimax nana 5.2%, Iodamoeba buetschlii 1.7%, Cryptosporidium sp. 2.3%. Multiple infection frequently occurred with 4 species as the maximum.