Non-synonymous mutations in the gene encoding vitamin K epoxide reductase (VKORC1) are responsible for resistance to anticoagulant rodenticides in rodents. Detection of resistant individuals is crucial to implement effective management plans and guarantee the success of eradication campaigns. Resistant individuals of the house mouse Mus musculus have been reported in several European countries and in North America. However, to date no data is available for M. musculus domesticus in Italy. In this study, we sequenced the three exons of the VKORC1 gene in 30 mice from the Pontine Archipelago, currently subject to an eradication campaign of invasive rodents. We recorded the presence of a mutation known to confer resistance to rodenticides (Tyr139Cys) in one individual (3.3% of the total samples set). Our data represent the first record of a resistant M. musculus domesticus in Italy.