Abstract The Parasitological Institute of the Slovak Academy of Sciences and the Section of Parasitology (formerly Institute of Parasitology) of the Department of Public Health Sciences of the Sapienza University of Rome have had a long term collaboration within several projects, starting with the first visiting fellowships in 1992 in Rome. Since then, the collaboration between the two institutions has continuously developed and has been focused mainly on the systematics of cestodes, starting in particular with the studies on the genetic polymorphism of fish Proteocephalus tapeworms in different host populations examined by enzyme electrophoresis. Some molecular studies have been later carried out on Eubothrium spp. and Echinococcus multilocularis, and most of our joint interest has been focused on Echinococcus granulosus and more recently, on Ascaris nematodes. The major achievements obtained during these years of collaboration are herein reported.