In the year 1993 repeated parasitological examinations of water and the equipment of an indoor school swimming pool were made. The sanitary and hygienic regime of the swimming pool was not respected and parasitological findings corresponded to this fact. Examinations of the swimming pool revealed the presence of helminths--Ascaris lumbricoides, Enterobius vermicularis and Taenia saginata, as well as of protozoa--Giardia intestinalis and Entamoeba coli. The parasites were detected in samples taken under operation conditions from free water, from walls of the swimming pool an from its equipment, as well as from the sediment in sand filters. The authors pointed out that increased occurrence of parasites was connected with exceeding of swimming pool capacity. They noted also massive occurrence of non-pathogenic protozoa in water and sediment of the swimming pool, which was considered an indicator of increased pollution. They drew attention to the possibility of infection with intestinal parasites present in the swimming pool water. The conditions are discussed which enable parasites to reach the stage in which they are can infect bathing people and cause parasitoses in them. The authors suggested which places of a swimming pool should be examined in the course of parasitological investigations. They took steps to prevent contamination of swimming pool water with developmental stages of parasites and to prevent their maturation.