Cytogenetic data are increasingly being used in taxonomic analyses and can also be used to investigate phylogenetic patterns. Additionally, studies on genotoxicity using cytogenetic analyses have been demonstrated as an useful tool for biomonitoring. The endangered limpet Patella ferruginea was investigated under karyo and cytological analyses in order to explore the taxonomic status of the two different forms of the species, the phylogenetic relationships and to show up its suitability for future biomonitoring programs. The haploid complement was of n = 9 (5 metacentric, 1 meta-submetacentric, 1 submetacentric, 1 subtelocentric, 1 telocentric), and the ideograms of the two forms failed to establish taxonomic separation between them. P. ferruginea is close to P. rustica according to the karyotypes and recent molecular studies. Finally, several nuclear abnormalities have been detected in the species that could be useful for monitoring the cytotoxic effects on the endangered populations of the species.