The new combination Xenolecia masafuerensis is made for Lecanora masafuerensis, a lichen species known from only two localities on Isla Alejandro Selkirk in the Juan Fernández archipelago, Chile. The species is fully described and illustrated and shown to be morphologically and chemically distinct from the similar X. spadicomma, which is known only from Chile and the Falkland Islands. The typification of X. masafuerensis and its distribution on the islands are also discussed. Key words: distribution, endemic species, Juan Fernandez islands, lichenized-fungi, typification.