Abstract: A survey of intestinal protozoa was made in 106 pilot sites of 28 counties in Zhejiang; a total of 55 291 residents were subject to stool examination. The detected intestinal protozoa included Entamoeba histolytica (1.5%), Entamoeba hartmanni (4.1%), Entamoeba coli (2.9%), Endolimax nana (5.9%), Iodamoeba buetschlii (0.5%), Giardia lamblia (3.8%), Blastocystis hominis (0.8%), Retortamonas intestinalis (0.07%), Chilomastix mesnili (0.007%), Balantidium coli (0.007%) and Isospora sp. (0.004%). Population , locality , and occupation based distribution of protozoan infections were analysed specially for E. histolytica, G. lamblia and Blastocystis hominis . The situation that G. lamblia infection mostly occurred in children below 15 years of age was noted, the infection rate being 6.8%. Significant difference in infection rate existed between places of low income and those of high income.