This contribution reports on the discovery of Calleida migratoria Casale, new species, a ground beetle previously unknown to the Galápagos Islands. Since the recent and very strong 1997–98 El Niño event we have found this species on five of the Galápagos Islands: Isabela, Pinta, Santa Cruz, Santiago and Rabida. The species is also known from Peru and its presence in Galápagos is therefore most probably another anthropogenic introduction which has taken advantage of the unusually favourable climatic circumstances of the last El Niño. Calleida migratoria is described and a provisional identification key is added to distinguish the new taxon from its closest relatives.