The Document, Assess, Monitoring, Act (DAMA) protocol details an approach to integrating information about parasites into large-scale studies of biodiversity, climate change, and emerging diseases. This study represents an effort to put the DAMA protocol into practice. We collected 101 individuals of protected ranid frogs belonging to the Pelophylax esculentus complex during 2012 and 2013 in the Hortobágy National Park (HNP) in eastern Hungary in an area where an inventory of amphibian helminths had been conducted 40 yr previously. Collecting sites included flowing water, a fish pond system, and a wetland marsh system. We found the following helminth species: Digeneans: Diplodiscus subclavatus, Haematoloechus variegatus, Opisthioglyphe ranae, Pleurogenes claviger, Pleurogenoides medians; Nematodes: Oswaldocruzia filiformis, Rhabdias esculentarum; and Acanthocephala: Acanthocephalus ranae. Rhabdais esculentarum is a new species for the Hungarian fauna and P. ridibundus represents a new host record for R. esculentarum while D. subclavatus, P. claviger, and P. medians are new species for the helminthofauna of the HNP. Our findings showed a significant discrepancy from the results of baseline inventories carried out 40 yr ago, although the reasons for this discrepancy are not clear. We suspect that the previously reported helminth species that we did not encounter are restricted to Pelophylax lessonae, a host we have not yet collected at this location, but factors associated with climate change or anthropogenic impacts cannot be ruled out.