The royal burial chamber of what is today the Collegiate-Basilica of St. Isidoro in León, Spain, built and remodeled between the 10th and 13th centuries and in the 20th century renamed the Kings' Pantheon, has 13 royal tombs that were opened in the presence of the Abbot-Prior of the Collegiate to enable a group of researchers to obtain all possible information from the royal remains. Several samples were sent to the Parasitology Unit of the Animal Pathology (Animal Health) Department at the Veterinary Faculty of León (Spain). In all the tombs, eggs and remains of nonparasitic mites were observed. In a piece of linen cloth from the bottom of 1 tomb, an Anoplocephala perfoliata egg was found. Furthermore, 4 mummified bodies were found. In 2 of these, those belonging to Infantes María and Fernando, Ascaris lumbricoides eggs were found and in the latter Trichuris trichiura eggs. We have not found in the literature reviewed any records of studies of this kind carried out in Spain.