A new, extinct species of Puffinus (Aves: Pro- cellariidae) is described from fossil bones found in caves in the west and north-west of South Island, New Zealand. The new species is smaller in all dimensions than either Puffinus gavia or P. huttoni, with which it forms a natural group. It is known from deposits dating from at least 20 000 years b.p. to others less than 600 years old. The distribution as presently known includes the west and north of the South Island, New Zealand, from Takaka Hill (41°S) in north-west Nelson, to near Punakaiki, at 42°S. The three taxa had allopatric breeding distributions. This is the first extinct procellariid to be described from New Zealand. As with other avian taxa that survived to the present millenium, it was probably exterminated by the Kiore Rattus exulans, which was introduced by Polynesians less than 1000 years ago.