Ectosymbiotic temnocephalan flatworms belonging to the genus Temnosewellia Damborenea and Cannon, 2001 were collected on Cherax destructor Clark, 1936 in an aquaculture farm in Sicily, Italy. This represents the first record of a temnocephalan species for the fauna of the island. Morphological and molecular identification of the collected specimens proved that they belong to the allochthonous species Temnosewellia minor Haswell, 1888, which was introduced along with crayfishes bred in aquaculture farms. The phylogenetic analyses carried out for the molecular identification of the Sicilian population highlighted some inconsistencies in the grouping of the Temnosewellia sequences available online, thus stressing the opportunity of a careful re-examination of the voucher samples and their identifications. The risks of a its unwary introduction in the wild and the need of monitoring its possible impacts on native biota are briefly discussed.