Extensive archaeological research including several environmental analyses was carried out in the historic centre of Chrudim in 2006. This article presents the results of the paleoparasitological investigation, which provided evidence of the level of hygiene and infestation of medieval and early modern populations (14th to 18th centuries). Organic settlements at the bottom of sewage dumps were especially rich sources of information on parasitic infestation. Five species of intestinal worms were identified with certainty: Trichuris trichiura, Ascaris lumbricoides, Toxocara canis/cati, Diphyllobothrium latum and Fasciola hepatica, and three others are considered likely: Hymenolepis nana, Enterobius vermicularis and Ancylostoma duodenale. Testing for the antigen GSA 65, evidence of Giardia lamblia, yielded positive results. The findings of the parasitological examination are evaluated in connection with the occurrence of parasites in humans, food quality and other health determinants of medieval populations.1