During July-August 1989, 219 coprological samples from primary school children from Niebla and Los Molinos localities (39 degrees 52'S, 73 degrees 26'W) in the coast of province of Valdivia, Chile, were analysed. Prevalence % (in parentheses) of infection by intestinal protozoa and helminths were the followings: Entamoeba histolytica: (18.0), Entamoeba coli (34.0), Endolimax nana (34.4), Iodamoeba buetschlii (7.4), Blastocystis hominis (64.3), Giardia intestinalis (27.9) Chilomastix mesnili (0.8), Ascaris lumbricoides (12.7), Trichuris trichiura (32.0), Trichostronqylidea gen. sp. (0.8), Enterobius vermicularis (1.6), Hymenolepis nana (0.4) Diphyllobothrium sp. (0.4). No sanitary conditions, water, faeces and garbage disposal were detected in the 55.5%, 86.4% and 52.7% of 110 houses from the sector, respectively. The high prevalence of protozoa and helminths intestinal infections in the sector are related to no sanitary conditions of houses and fecal contamination of the estuary of the Valdivia river.