The skeleton of a large bird from Late Oligocene marine strata of the Tokoro Formation, exposed near Abashiri City in northeastern Hokkaido, Japan, represents a new genus and species of the extinct pelecaniform family Plotopteridae. This new specimen, Hokkaidornis abashiriensis new gen. et sp., was similar in size to Copepteryx hexeris Olson and Hasegawa, but differs from that species chiefly in characters of the anterior parts of the skeleton. The leg bones of H. abashiriensis and C. hexeris are nearly identical, and if found isolated, probably would be deemed congeneric/conspecific. The new animal from Hokkaido demonstrates that plotopterid generic diversity during Late Oligocene time was greater than previously suspected.