Recent research findings suggest that introduced species show a low or no parasite burden in their new habitats. This can result in an increased growth, better reproduction and consequently an advantage in competition with native species. Surveys on a local scale and investigations of other species are needed to confirm this general assumption.We here compare three native (Littorina littorea, Mytilus edulis and Cerastoderma edule) and three introduced mollusc species (Crepidula fornicata, Crassostrea gigas and Ensis americanus/directus) as intermediate hosts for parasites. Samples of 40-50 individuals of these species pairs (native-introduced) were taken at the same location and at the same time in two tidal basins in the north and south of the island of Sylt. Results show that the introduced species investigated are infected by the same native parasite species (mainly trematodes) as their native counterparts. However, prevalence and intensity are lower in the majority of cases. Non-native parasites imported with the introduced molluscs were not found.