Background and aims: The genus Matthiola W. T. Aiton comprises between 50 and 60 species native to the Mediterranean, Central Asia and South Africa. M. incana (L.) W. T. Aiton, indigenous to southern Europe, is naturalized in other regions of the world. In Argentina it is cultivated as ornamental. From floristic observations, a naturalized population was found, which self-perpetuates without human intervention, on the coasts of the Patagonia Argentina. The objective of this work is to report for the first time the naturalization of M. incana in Argentina. M&M: For the identification of the species, the classic methods of taxonomy were followed, specific bibliography was consulted and the collected material was contrasted with digital images of the lectotype. Seeds were collected from the naturalized population and the germinative power was evaluated through a germination test. The collected material that documents the present work was deposited in the ARC herbarium of the Universidad Nacional del Comahue. Results: Matthiola incana is described. The common names and data on distribution, habitat, ecology and uses are included. Photographs are presented to complement the description. The germination test showed that 95% of the seeds germinated after 24 hours at 25 degrees C. Conclusions: The naturalization of Matthiola incana is reported for the first time in Argentina, the only species of the genus in the country until now.